Minor fixes for chan_skinny

Whitespace, change SUBSTATE_ONHOOK to correct SKINNY_ONHOOK and 
correct len of 2 strcmp in skinny_setdebug(). (see opticron's review
on https://reviewboard.asterisk.org/r/2240/)
........

Merged revisions 377991 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@378001 65c4cc65-6c06-0410-ace0-fbb531ad65f3