Unix CM: Purge needless brackets

Doing if ((a==b)) is unecessary. It's also potentially dangerous, as
that's the syntax required to do assignment within an if statement.
clang now issues warnings (errors in -Werror mode) when it encounters
these.

Remove pointless braces from the Unix CM to make clang happy.

Reviewed-on: http://gerrit.openafs.org/7074
Reviewed-by: Derrick Brashear <shadow@dementix.org>
Tested-by: Derrick Brashear <shadow@dementix.org>
(cherry picked from commit 345656ec140f0156f2076629bdfc84940c02160b)

Change-Id: I6a47d30fd6ef0ad0c6903c79a0bfe579db527847
Reviewed-on: http://gerrit.openafs.org/10743
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>