fix(macos): fix software inventory when proxy is used

Don't validate XML against DTD to skip downloading DTD as it would
fail if a proxy is enable.

Closes fusioninventory#453

Changes

@@ -12,6 +12,8 @@ inventory:
 * Fix #442: kaspersky not fully recognized in russia
 * Fix #501: wrong status was reported when windows defender was disabled
 * Enhanced software inventory under Arch Linux
+* Fix #453: under MacOS, skip XML DTD validation for software inventory as
+  parsing may fail if a proxy is enabled
 
 deploy:
 * Bump Deploy task version to 2.7

lib/FusionInventory/Agent/Tools/MacOS.pm

@@ -46,6 +46,10 @@ sub _initXmlParser {
     } elsif ($params{file}) {
         $xmlParser = XML::XPath->new(filename => $params{file});
     }
+
+    # Don't validate XML against DTD, parsing may fail if a proxy is active
+    $XML::XPath::ParseParamEnt = 0;
+
     return $xmlParser;
 }