Update mp4 dependency to include openssl

mp4 code was changed earlier which uses openssl in some way but the
dependency was not updated.

Issue: 15

Change-Id: Icababe00753f739832d61bc6792d95321cc59cf5

packager/media/formats/mp4/mp4.gyp

@@ -56,6 +56,7 @@
         'track_run_iterator.h',
       ],
       'dependencies': [
+        '../../../third_party/openssl/openssl.gyp:openssl',
         '../../base/media_base.gyp:base',
       ],
     },