protobuf: Update to new upstream version 2.5.0.

Starting from version 32, Chromium now relies on protobuf version 2.5.0,
so let's update it, especially because it doesn't have backwards
compatible changes in the release notes.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
chromium: Update all channels to latest versions.

This introduces version 31.0.1650.57 as the new version for the stable
channel.

Overview of the updated channels:

stable: 30.0.1599.114 -> 31.0.1650.57
beta:   31.0.1650.34  -> 32.0.1700.19
dev:    32.0.1671.3   -> 33.0.1712.4

This drops the sandbox_userns_30.patch as version 30 is no longer
stable. In addition, we had to patch out some references to /usr/bin/gcc
in the bundled WebKit sources.

Builds are passing and running fine.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>