Update sngrep.sh

debian/resources/sngrep.sh

@@ -21,7 +21,7 @@ else
 	if [ ."$os_codename" = ."jessie" ]; then
 		echo "deb http://packages.irontec.com/debian $os_codename main" > /etc/apt/sources.list.d/sngrep.list
 		wget http://packages.irontec.com/public.key -q -O - | apt-key add -
+  		apt-get update
 	fi
-	apt-get update
 	apt-get install -y sngrep
 fi