Issue #2737785 by ergonlogic: Provide a stable location for Drush overrides

Provision/Config/Drushrc/provision_drushrc_aegir.tpl.php

@@ -5,6 +5,11 @@
  */
 print "<?php \n\n";
 
+print "# !!!WARNING!!! This file is re-generated on each verify of the hostmaster site.\n";
+print "# Any changes tou make to this file will thus soon be lost. Instead, create a\n";
+print "# file called 'local.drushrc.php' in the same directory as this one (i.e.\n";
+print "# '/var/aegir/.drush/'), and add any custom configuration there.\n";
+
 print "# A list of Aegir features and their enabled status.\n";
 print "\$options['hosting_features'] = ". var_export($hosting_features, TRUE) . ";\n\n";
 
@@ -14,4 +19,7 @@ print "\$options['exclude'] = ". var_export($drush_exclude, TRUE) . ";\n\n";
 print "# A list of paths that drush should include even when working outside\n";
 print "# the context of the hostmaster site.\n";
 print "\$options['include'] = ". var_export($drush_include, TRUE) . ";\n";
+
+print "# Local non-aegir-generated additions.";
+print "@include_once(dirname(__FILE__) . '/local.drushrc.php');";
 ?>