update_psa: when called with an argument, skip test for available

updates, executing 'git pull' in any case.

update_psa_impl

@@ -28,11 +28,13 @@ collect_current_configuration () {
     #done
 }
 
-update_psa() {
+update_psa() { # calling with a parameter is used for testing
 
+    if [ $# -eq 0 ]; then
         if ! updates_available; then    # check for false alarm
             update_psa_false_alarm "update requested, but no WAIT state detected"
-        exit $?
+            exit $EXITCODE
+        fi
     fi
 
     update_psa_activated    # message to ISMAS