Stop building NSS on Windows.

Since the GYP variables use_openssl and build_ssl are both
enabled by default on Windows today, I believe we should be able
to clean up the GYP paths that build NSS for Windows.

BUG=4497
TESTED=Passing tryjobs with --clobber specified.
R=pthatcher@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/50559004

Cr-Commit-Position: refs/heads/master@{#8945}
1 file changed