Print (raw) exit code on system() failure

Change-Id: I5d99319aa336c02dc0c20ab2bc3a1302840d100d
Reviewed-on: https://gerrit.libreoffice.org/59242
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

solenv/bin/modules/installer/simplepackage.pm

@@ -457,7 +457,7 @@ sub create_package
 
         if ($returnvalue)
         {
-            $infoline = "ERROR: Could not execute \"$systemcall\"!\n";
+            $infoline = "ERROR: Could not execute \"$systemcall\": $returnvalue\n";
             push( @installer::globals::logfileinfo, $infoline);
         }
         else