clang compiler warnings: Fix -Wparantheses-equality warnings

Clang will treat ((a == b)) as a warning, as it reasonably expects that the
developer may have intended to write (a == b) or ((a = b)). This patch cleans
up all instances where equality, not assignment, was intended between two
parantheses.

Review: https://reviewboard.asterisk.org/r/4531/

ASTERISK-24917
Repoted by: dkdegroot
patches:
  rb4531.patch submitted by dkdegroot (License 6600)
........

Merged revisions 433687 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/13@433688 65c4cc65-6c06-0410-ace0-fbb531ad65f3