Fix userID memory corruption and tweak changelog.

Author: Michael Lehenbauer

Firestore/CHANGELOG.md

@@ -2,10 +2,10 @@
 
 # v0.10.3
 - [fixed] Fixed a regression in the 4.10.0 Firebase iOS SDK release that
-  prevented the SDK from communicating with the backend until successfully
-  authenticating via Firebase Authentication. All reads and writes would
-  silently be executed only locally rather than being sent as unauthenticated
-  requests.
+  prevented the SDK from communicating with the backend before successfully
+  authenticating via Firebase Authentication or after unauthenticating and
+  re-authenticating. Reads and writes would silently be executed locally
+  but not sent to the backend.
 
 # v0.10.2
 - [changed] When you delete a FirebaseApp, the associated Firestore instances

Firestore/Source/Local/FSTLevelDBMutationQueue.mm

@@ -94,7 +94,7 @@ @implementation FSTLevelDBMutationQueue {
 + (instancetype)mutationQueueWithUser:(const User &)user
                                    db:(std::shared_ptr<DB>)db
                            serializer:(FSTLocalSerializer *)serializer {
-  NSString *userID = user.is_authenticated() ? util::WrapNSStringNoCopy(user.uid()) : @"";
+  NSString *userID = user.is_authenticated() ? util::WrapNSString(user.uid()) : @"";
 
   return [[FSTLevelDBMutationQueue alloc] initWithUserID:userID db:db serializer:serializer];
 }