Add braces where missing and a few whitespace fixes in sig_analog

(closes issue #15678)
Reported by: alecdavis
Patches:
      sig_analog_mainly_braces.diff.txt uploaded by alecdavis (license 585)
Tested by: alecdavis


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@212291 65c4cc65-6c06-0410-ace0-fbb531ad65f3