Clear the Google token, to ensure it isn't stored

Firebase's JWT is still stored until it expires, but the Google token
isn't

Author: puf

library/src/main/java/com/firebase/ui/auth/google/GoogleOAuthTask.java

@@ -23,6 +23,8 @@ protected String doInBackground(String... emails) {
 
         try {
             token = GoogleAuthUtil.getToken(mContext, emails[0], "oauth2:profile email");
+            // since we're immediately exchanging this token for a Firebase JWT token, we don't need to store it
+            GoogleAuthUtil.clearToken(mContext, token);
         } catch (UserRecoverableAuthException e) {
             Log.e(TAG, "Error getting token", e);
         } catch (GoogleAuthException e) {