gnutls: Fix minor memory leak when trying blank passwords
gnutls: Fix minor memory leak when trying blank passwords

Commit 99f22b9d3 (Handle empty (but not NULL) passwords on PKCS#12 certs)
introduced a possible memory leak if gnutls_pkcs12_verify_mac(p12, "")
returned an error other than GNUTLS_E_MAC_VERIFY_FAILED.  Simplify the
check so that it only sets an empty password if MAC verification passes.

Spotted by Coverity.

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

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