cleanup: add logAndExit() for cephcsi:main() to call instead of panic

The main() function of the cephcsi executable calls klog.Fatalln() to
report certain errors. This causes the executable to panic which is not
helpful to users that only need the error message.

By introducing logAndExit(), there is no need to call klog.Fatalln()
anymore.

Signed-off-by: Niels de Vos <ndevos@redhat.com>

cmd/cephcsi.go

@@ -208,3 +208,8 @@ func validateMaxSnaphostFlag(conf *util.Config) {
 		klog.Fatalln("maxsnapshotsonimage flag value should be between 1 and 500")
 	}
 }
+
+func logAndExit(msg string) {
+	klog.Errorln(msg)
+	os.Exit(1)
+}