Fix memory leak if openconnect_hash_yubikey_password() fails
Fix memory leak if openconnect_hash_yubikey_password() fails

Slightly overengineered for now because we're going to need the PIN
again for working around the Yubikey PBKDF2 issues.

Signed-off-by: David Woodhouse <b460d66aaf00c296a3db1c1d9eeafc081d5f7d70@intel.com>

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