- replace some nested 'if' with '&&'

- bring the short case at the top of an 'if' statement
  (also fix misformatting)
- replace several 'if' with the '?' operator;
 
- invert the condition on an 'if' to reduce the nesting depth 
  (reindentation to be done later).



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@20454 65c4cc65-6c06-0410-ace0-fbb531ad65f3