A followup to r6828 to fix a condition check in mediasession.cc.
A followup to r6828 to fix a condition check in mediasession.cc.

BUG=2395
R=juberti@chromium.org, juberti@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/17029004

Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 56d8e05238a46bfc51fcb804bc1f5477dfefcc14

sippet/talk,sippet/talk,sippet/talk,sippet/talk,sippet/talk