cstp: Close socket after failed connection attempt
cstp: Close socket after failed connection attempt

Currently the code just relies on exit() to clean everything up, but that
only works for a standalone app.

Signed-off-by: Kevin Cernekee <3105dbb3dd63fbb4f6371cfb04adc6726f76c56b@gmail.com>

mtmiller/openconnect,don-johnny/openconnect,lins05/openconnect,nmav/openconnect-mine,matlockx/openconnect,brandt/openconnect,mveplus/openconnect-client,chadcatlett/openconnect,mveplus/openconnect-client,don-johnny/openconnect,brandt/openconnect,chadcatlett/openconnect,neshema/openconnect,matlockx/openconnect,matlockx/openconnect,cernekee/openconnect,lins05/openconnect,lins05/openconnect,atyndall/openconnect,cernekee/openconnect,atyndall/openconnect,nmav/openconnect-mine,neshema/openconnect,matlockx/openconnect,mtmiller/openconnect,atyndall/openconnect,brandt/openconnect,brandt/openconnect,neshema/openconnect,don-johnny/openconnect,liiir1985/openconnect,atyndall/openconnect,neshema/openconnect,cernekee/openconnect,chadcatlett/openconnect,don-johnny/openconnect,liiir1985/openconnect,mveplus/openconnect-client,nmav/openconnect-mine,mtmiller/openconnect,cernekee/openconnect,lins05/openconnect,liiir1985/openconnect,chadcatlett/openconnect,mveplus/openconnect-client,liiir1985/openconnect,mtmiller/openconnect,nmav/openconnect-mine