AVRCP_BROWSE: Inserting check for externalPath length

There are few players which do not have root folder
and because of that there external path length is 0.
Hence instead of trimming their root folder we push
mediaId in stack during SetBrowse.

CRs-Fixed: 2425117
Change-Id: Ia3eb255ad426b1cecdf0af7afbb26093fbda3068
1 file changed