Actually disable collision-protect in parallel_emerge.

Actually disable collision-protect in parallel_emerge.

I tried to disable parallel_emerge yesterday, but my change didn't work,
so the buildbots are still running into occasional related issues.

Portage has two flags for doing collision protection: collision-protect
and protect-owned. The protect-owned feature is enabled by default and
is quite useful: it checks to make sure that we don't have multiple
packages that own the same file. The collision-protect feature is more
strict, and less useful: it fails if it finds a conflicting file, even
if that file was created by an earlier ebuild that failed to install.

We want to disable collision-protect here because we don't handle
failures during the merge step very well -- we just leave the old
Unfortunately, we haven't quite figure out the best way to handle
these failures in parallel emerge, so for now we disable the flag.

TEST=Created a fake collision, made sure that packages still merge.
BUG=none

[Nick Sanders, 2010-07-30 06:22:08]

lgtm w/ typo fix

http://codereview.chromium.org/2825076/diff/1/2
File parallel_emerge (right):

http://codereview.chromium.org/2825076/diff/1/2#newcode327
parallel_emerge:327: # Unfortunately, we haven't quite figure out the best way
to handle
typos