remove unused preKeyLastResort

SignalServiceKit/src/Account/TSPreKeyManager.m

@@ -146,7 +146,6 @@ static const NSUInteger kMaxPrekeyUpdateFailureCount = 5;
         NSString *description;
         if (modeCopy == RefreshPreKeysMode_SignedAndOneTime) {
             description = @"signed and one-time prekeys";
-            PreKeyRecord *lastResortPreKey = [primaryStorage getOrGenerateLastResortKey];
             preKeys = [primaryStorage generatePreKeyRecords];
             // Store the new one-time keys immediately, before they are sent to the
             // service to prevent race conditions and other edge cases.
@@ -154,8 +153,7 @@ static const NSUInteger kMaxPrekeyUpdateFailureCount = 5;
 
             request = [OWSRequestFactory registerPrekeysRequestWithPrekeyArray:preKeys
                                                                    identityKey:identityKeyPair.publicKey
-                                                                  signedPreKey:signedPreKey
-                                                              preKeyLastResort:lastResortPreKey];
+                                                                  signedPreKey:signedPreKey];
         } else {
             description = @"just signed prekey";
             request = [OWSRequestFactory registerSignedPrekeyRequestWithSignedPreKeyRecord:signedPreKey];

SignalServiceKit/src/Network/API/Requests/OWSRequestFactory.h

@@ -67,8 +67,7 @@ typedef NS_ENUM(NSUInteger, TSVerificationTransport) { TSVerificationTransportVo
 
 + (TSRequest *)registerPrekeysRequestWithPrekeyArray:(NSArray *)prekeys
                                          identityKey:(NSData *)identityKeyPublic
-                                        signedPreKey:(SignedPreKeyRecord *)signedPreKey
-                                    preKeyLastResort:(PreKeyRecord *)preKeyLastResort;
+                                        signedPreKey:(SignedPreKeyRecord *)signedPreKey;
 
 + (TSRequest *)remoteAttestationRequest:(ECKeyPair *)keyPair
                               enclaveId:(NSString *)enclaveId

SignalServiceKit/src/Network/API/Requests/OWSRequestFactory.m

@@ -235,12 +235,10 @@ NS_ASSUME_NONNULL_BEGIN
 + (TSRequest *)registerPrekeysRequestWithPrekeyArray:(NSArray *)prekeys
                                          identityKey:(NSData *)identityKeyPublic
                                         signedPreKey:(SignedPreKeyRecord *)signedPreKey
-                                    preKeyLastResort:(PreKeyRecord *)preKeyLastResort
 {
     OWSAssertDebug(prekeys.count > 0);
     OWSAssertDebug(identityKeyPublic.length > 0);
     OWSAssertDebug(signedPreKey);
-    OWSAssertDebug(preKeyLastResort);
 
     NSString *path = textSecureKeysAPI;
     NSString *publicIdentityKey = [[identityKeyPublic prependKeyType] base64EncodedStringWithOptions:0];
@@ -252,7 +250,6 @@ NS_ASSUME_NONNULL_BEGIN
                               method:@"PUT"
                           parameters:@{
                               @"preKeys" : serializedPrekeyList,
-                              @"lastResortKey" : [self dictionaryFromPreKey:preKeyLastResort],
                               @"signedPreKey" : [self dictionaryFromSignedPreKey:signedPreKey],
                               @"identityKey" : publicIdentityKey
                           }];

SignalServiceKit/src/Storage/AxolotlStore/OWSPrimaryStorage+PreKeyStore.h

@@ -7,8 +7,7 @@
 
 @interface OWSPrimaryStorage (PreKeyStore) <PreKeyStore>
 
-- (NSArray *)generatePreKeyRecords;
-- (PreKeyRecord *)getOrGenerateLastResortKey;
+- (NSArray<PreKeyRecord *> *)generatePreKeyRecords;
 - (void)storePreKeyRecords:(NSArray *)preKeyRecords;
 
 @end

SignalServiceKit/src/Storage/AxolotlStore/OWSPrimaryStorage+PreKeyStore.m

@@ -16,19 +16,7 @@
 
 @implementation OWSPrimaryStorage (PreKeyStore)
 
-- (PreKeyRecord *)getOrGenerateLastResortKey
-{
-    if ([self containsPreKey:kPreKeyOfLastResortId]) {
-        return [self loadPreKey:kPreKeyOfLastResortId];
-    } else {
-        PreKeyRecord *lastResort =
-            [[PreKeyRecord alloc] initWithId:kPreKeyOfLastResortId keyPair:[Curve25519 generateKeyPair]];
-        [self storePreKey:kPreKeyOfLastResortId preKeyRecord:lastResort];
-        return lastResort;
-    }
-}
-
-- (NSArray *)generatePreKeyRecords
+- (NSArray<PreKeyRecord *> *)generatePreKeyRecords;
 {
     NSMutableArray *preKeyRecords = [NSMutableArray array];