Fix uninitialized variable.  If FindConstraint() returns false, we check |value| in two places and at that point, it can hold an uninitialized value.  Caught by Linux Memcheck builder.
Fix uninitialized variable.  If FindConstraint() returns false, we check |value| in two places and at that point, it can hold an uninitialized value.  Caught by Linux Memcheck builder.

http://chromegw.corp.google.com/i/client.webrtc/builders/Linux%20Memcheck/builds/3351/steps/libjingle_peerconnection_unittest/logs/0A34BA777AB03D08

TBR=perkj@webrtc.org
BUG=

Review URL: https://webrtc-codereview.appspot.com/43579004

Cr-Original-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#8611}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 5af41aabae428f261702ef287d8f07b198a7f9ba

dcpang/fatline-libjingle,dcpang/fatline-libjingle,sippet/talk,sippet/talk,dcpang/fatline-libjingle,sippet/talk,dcpang/fatline-libjingle,sippet/talk,dcpang/fatline-libjingle,sippet/talk