Fix search bar crash on older iOS versions

Signal/Signal-Info.plist

@@ -5,9 +5,9 @@
 	<key>BuildDetails</key>
 	<dict>
 		<key>CarthageVersion</key>
-		<string>0.33.0</string>
+		<string>0.34.0</string>
 		<key>OSXVersion</key>
-		<string>10.15</string>
+		<string>10.15.1</string>
 		<key>WebRTCCommit</key>
 		<string>1445d719bf05280270e9f77576f80f973fd847f8 M73</string>
 	</dict>

Signal/src/Loki/Components/SearchBar.swift

@@ -19,6 +19,12 @@ final class SearchBar : UISearchBar {
         setImage(searchImage, for: .search, state: .normal)
         let clearImage = #imageLiteral(resourceName: "searchbar_clear").asTintedImage(color: Colors.searchBarPlaceholder)!
         setImage(clearImage, for: .clear, state: .normal)
+        let searchTextField: UITextField
+        if #available(iOS 13, *) {
+            searchTextField = self.searchTextField
+        } else {
+            searchTextField = self.value(forKey: "_searchField") as! UITextField
+        }
         searchTextField.backgroundColor = Colors.searchBarBackground // The search bar background color
         searchTextField.textColor = Colors.text
         searchTextField.attributedPlaceholder = NSAttributedString(string: NSLocalizedString("Search", comment: ""), attributes: [ .foregroundColor : Colors.searchBarPlaceholder ])