Suppress leak in BasicNetworkManager in remoting test

TBR=sergeyu@chromium.org
BUG=115647
TEST=none

Review URL: https://chromiumcodereview.appspot.com/9460005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@123481 0039d316-1c4b-4281-b951-d872f2087c98