fix: empty file list for initial commit

[vvch]

The file list for initial commit was always empty. This patch fixes the issue.

[tibirna]

Excellent catch! I guess it was a remnant of early git releases without the --root option on diff-tree. Thank you!

[vvch]

Maybe you are right. --root option was introduced in 2005 even before git v1.0 whereas initial qgit import commit was in 2006 and it already had parentsCount() == 0 skip condition. But seems like it had been developed long before.

[vvch]

No, I was confused :)
--root option was added on May 20 2005 but first git commit was on Apr 8 2005. That is git existed only 6 weeks without --root in diff-tree. It is a very little chance that qgit was developed in such a short period :)