Rename the GLES2 namespace to gl2. BUG=18110152 Change-Id: Ia1ec422b26b7f8d5edf856d3b625a0e9ebd5d31b Reviewed-on: https://swiftshader-review.googlesource.com/1250 Reviewed-by: Nicolas Capens <nicolascapens@google.com> Tested-by: Nicolas Capens <nicolascapens@google.com>