fix bug: release mDisconnectLock when early terminate

Bug: 134995545
Test: described in buganizer comment #2
Change-Id: Ie134e503cd7602a754b57bcc5c1355dea19d4eab
(cherry picked from commit 5dbd5a39e4cee6d5f0207c636f690d204509d7dc)
diff --git a/media/libmediaplayerservice/nuplayer/GenericSource.cpp b/media/libmediaplayerservice/nuplayer/GenericSource.cpp
index 5c77e41..0f72c0d 100644
--- a/media/libmediaplayerservice/nuplayer/GenericSource.cpp
+++ b/media/libmediaplayerservice/nuplayer/GenericSource.cpp
@@ -389,7 +389,6 @@
                 if (httpSource == NULL) {
                     ALOGE("Failed to create http source!");
                     notifyPreparedAndCleanup(UNKNOWN_ERROR);
-                    mDisconnectLock.lock();
                     return;
                 }
                 mDisconnectLock.lock();
@@ -449,6 +448,7 @@
 
         if (mDataSource == NULL) {
             ALOGE("Failed to create data source!");
+            mDisconnectLock.unlock();
             notifyPreparedAndCleanup(UNKNOWN_ERROR);
             return;
         }