stagefright-plugins: Fix mov file streaming

stagefright-plugins: Fix mov file streaming

mov file is consider as MEDIA_MIMETYPE_CONTAINER_MPEG4.
But if we are streaming, the following code will force
to use aosp extractor instead:
    if (!strcasecmp(container, MEDIA_MIMETYPE_CONTAINER_MPEG4)
            && (source->flags() & DataSource::kIsCachingDataSource)) {
        ALOGI("support container: %s, but it is caching data source, "
                "Don't use ffmpegextractor", container);
        (*meta)->clear();
        *meta = NULL;
        return false;
    }

However aosp does not support mov file container, which results
playback fails.

This patch fixes it.

Change-Id: Ie2ae8a177c7df92987b6a955e6450cb69ee9f93e