make search hint translatable

Fixes #3261
Closes #3262

//FREEBIE

res/values/strings.xml

@@ -139,6 +139,9 @@
     <string name="ConversationFragment_deleting">Deleting...</string>
     <string name="ConversationFragment_deleting_messages">Deleting messages...</string>
 
+    <!-- ConversationListActivity -->
+    <string name="ConversationListActivity_search">Search...</string>
+
     <!-- ConversationListFragment -->
     <string name="ConversationListFragment_delete_threads_question">Delete threads?</string>
     <string name="ConversationListFragment_are_you_sure_you_wish_to_delete_all_selected_conversation_threads">Are you sure you wish to delete ALL selected conversation threads?</string>

src/org/thoughtcrime/securesms/ConversationListActivity.java

@@ -106,6 +106,7 @@ public class ConversationListActivity extends PassphraseRequiredActionBarActivit
 
   private void initializeSearch(MenuItem searchViewItem) {
     SearchView searchView = (SearchView)MenuItemCompat.getActionView(searchViewItem);
+    searchView.setQueryHint(getString(R.string.ConversationListActivity_search));
     searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
       @Override
       public boolean onQueryTextSubmit(String query) {