DRTVWR-418: Binary search for a good size for temp Mac disk image

indra/newview/viewer_manifest.py

@@ -980,7 +980,7 @@ def package_finish(self):
         # make sure we don't have stale files laying about
         self.remove(sparsename, finalname)
 
-        self.run_command('hdiutil create %(sparse)r -volname %(vol)r -fs HFS+ -type SPARSE -megabytes 2000 -layout SPUD' % {
+        self.run_command('hdiutil create %(sparse)r -volname %(vol)r -fs HFS+ -type SPARSE -megabytes 1500 -layout SPUD' % {
                 'sparse':sparsename,
                 'vol':volname})