[radtest] Allow spaces in shared secret

Hi. A (very) little fix to allow usage of spaces in shared secret with radtest. --- /usr/bin/radtest 2010-11-08 09:38:23.016945454 +0100 +++ /home/cedric.carree/radtest 2010-11-09 09:51:46.012445301 +0100 @@ -50,6 +50,6 @@ then echo "Framed-Protocol = PPP" fi -) | $radclient $DICTIONARY -x $3 auth $5 +) | $radclient $DICTIONARY -x $3 auth "$5" exit $?