fdo#47689: Avoid crashing mdworker: Don't use uninitialized variable

It's the isCustom field that should be checked to see whether the
customAttribute field has been assigned or not.

Change-Id: I5d2af26b675ab0cbc0e1844eb98ebaf5145eb73d
Avoid use of nonexistent variable evem in commented-out code

Change-Id: Icc9def55a814fc1309ce143a84effc140a90a92b
Fix indentation

Change-Id: I93309674ef50e8ca7438874378fb01484bb7f9f3