rpc: gss: eliminate print_hexl()'s

Dumping all this data to the logs is wasteful (even when debugging is turned
off), and creates too much output to be useful when it's turned on.

Fix a minor style bug or two while we're at it.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>