[__file] Treat pre-exists as a special case in gencode-remote as it should never get there

cdist/conf/type/__file/gencode-remote

@@ -61,7 +61,7 @@ set_mode() {
 }
 
 case "$state_should" in
-    present|exists|pre-exists)
+    present|exists)
         # Note: Mode - needs to happen last as a chown/chgrp can alter mode by
         #  clearing S_ISUID and S_ISGID bits (see chown(2))
         for attribute in group owner mode; do
@@ -83,7 +83,11 @@ case "$state_should" in
             # set-attributes is created if file is created or uploaded in gencode-local
             fire_onchange=1
         fi
+    ;;
 
+    pre-exists)
+        # pre-exists should never reach gencode-remote…
+        exit 1
    ;;
 
     absent)