play low resolution .webm or .ogv file, no video but has sound

[cmchen6585]

V1.03.01 has the problem, V1.02.01 is OK.

Video clip for test.
https://docs.google.com/file/d/0BzjNDiX4S39daFFpTFljeVR5S00/edit
https://docs.google.com/file/d/0BzjNDiX4S39daFFpTFljeVR5S00/edit

[trungnt]

A quick fix: apc-io/apc_b2g_gaia@70e1704.

Create an issue for this on Mozilla's bugzilla at https://bugzilla.mozilla.org/show_bug.cgi?id=975262,