Revert "Set installation to fcm now. (parse-community#820)"

This reverts commit f3d47f6.

Author: rogerhu

fcm/src/main/java/com/parse/fcm/ParseFirebaseJobService.java

@@ -26,7 +26,6 @@
 public class ParseFirebaseJobService extends JobService {
 
     private static final String JOB_TAG_UPLOAD_TOKEN = "upload-token";
-    private static final String PUSH_TYPE = "fcm";
 
     static Job createJob(FirebaseJobDispatcher dispatcher) {
         return dispatcher.newJobBuilder()
@@ -51,7 +50,7 @@ public boolean onStartJob(final JobParameters job) {
         if (installation != null && token != null) {
             installation.setDeviceToken(token);
             //even though this is FCM, calling it gcm will work on the backend
-            installation.setPushType(PUSH_TYPE);
+            installation.setPushType("gcm");
             installation.saveInBackground(new SaveCallback() {
                 @Override
                 public void done(ParseException e) {