Apparently IsOzone and IsLinux can both be true at the same time. This was
confounding the config detection.

Bug: angleproject:2286
Bug: chromium:928583
Change-Id: Ifd28242f396fd97447720b0c11caf8c1590f7222
Reviewed-on: https://chromium-review.googlesource.com/c/1454319Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>