Fix < 0 comparison for an unsigned long long (#5353)

* Fix < 0  comparison for an unsigned long long

* Remove an unused file and fix init of a ULL

Author: mikehaney24

GoogleDataTransport/GDTCORLibrary/GDTCOREvent.m

@@ -40,11 +40,11 @@ + (NSNumber *)nextEventID {
                                                     encoding:NSUTF8StringEncoding
                                                        error:&error];
     const char *countChars = [countText UTF8String];
-    unsigned long long count = -1;
+    unsigned long long count = 0ULL;
     if (countChars) {
       count = strtoull([countText UTF8String], NULL, 10);
     }
-    nextEventID = error || count < 0 ? 0 : count;
+    nextEventID = error ? 0 : count;
   });
 
   __block NSNumber *result;