watchdog.sh: do not exit in --source-only

bats will source 02_watchdog.sh. Move all checks that may exit in the
branch when --source-only is not passed to avoid a false negative in
bats.

Signed-off-by: Eric Chanudet <echanude@redhat.com>

usr/lib/greenboot/check/required.d/02_watchdog.sh

@@ -42,14 +42,14 @@ check_if_current_boot_is_wd_triggered() {
     fi
 }
 
-if ! check_if_there_is_a_watchdog ; then
-  echo "No watchdog on the system, skipping check"
-  exit 0
-fi
-
 # This is in order to test check_if_current_boot_is_wd_triggered
 # function within a container
 if [ "${1}" != "--source-only" ]; then
+  if ! check_if_there_is_a_watchdog ; then
+    echo "No watchdog on the system, skipping check"
+    exit 0
+  fi
+
   source_configuration_file
   if [ "${GREENBOOT_WATCHDOG_CHECK_ENABLED,,}" != "true" ]; then
     echo "Watchdog check is disabled"