fix some little issues on big endian platforms to resolve compiler warnings

 - don't call the byte swapping macros on single byte numbers
 - don't do a ++ increment in the argument in the argument to the byte swapping
   macros. This gets expanded to incrementing the variable 4 times in a single
   operation, which results in undefined (and obviously undesired) behavior. :)


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@35766 65c4cc65-6c06-0410-ace0-fbb531ad65f3