switch to use sendmail for Swiftmailer default (more universal)

recipes/symfony/swiftmailer-bundle/etc/packages/swiftmailer.yaml

@@ -1,5 +1,5 @@
 swiftmailer:
-    transport: smtp
+    transport: sendmail
     host: "%env(MAILER_HOST)%"
     username: "%env(MAILER_USERNAME)%"
     password: "%env(MAILER_PASSWORD)%"

recipes/symfony/swiftmailer-bundle/manifest.json

@@ -6,7 +6,7 @@
         "etc/": "%ETC_DIR%/"
     },
     "env": {
-        "MAILER_HOST": "127.0.0.1",
+        "MAILER_HOST": "",
         "MAILER_USERNAME": "",
         "MAILER_PASSWORD": ""
     }