Wrap EXPAND(..) macro with a do-while(0) loop and put a single statement on each line

As a positive side-effect, this eliminates the double semicolons reported by Coverity:
the macro contained a trailing semicolon, in addition to the semicolon placed on
each line where EXPAND(..) was called.

MFC after: 1 week
Reported by: Coverity
CID: 1194269
Sponsored by: EMC / Isilon Storage Division