Move the global password for files external to post

Again more false positives in some scanners

Signed-off-by: Roeland Jago Douma <roeland@famdouma.nl>

apps/files_external/templates/settings.php

@@ -205,7 +205,7 @@ function writeParameterInput($parameter, $options, $classes = []) {
 
 <div class="followupsection">
 	<form autocomplete="false" action="#"
-		  id="global_credentials">
+		  id="global_credentials" method="post">
 		<h2><?php p($l->t('Global credentials')); ?></h2>
 		<p class="settings-hint"><?php p($l->t('Global credentials can be used to authenticate with multiple external storages that have the same credentials.')); ?></p>
 		<input type="text" name="username"