archive: Drop unnecessary empty comments and 'final' qualifiers on locals

archive: Drop unnecessary empty comments and 'final' qualifiers on locals

Early JGit code used comments to inform the Eclipse formatter about
where to break lines and used final in the hope of making code faster.
The ArchiveCommand command implementation imitated that style.

Nowadays the project relies less on the Eclipse formatter and relies
more on Java having sane performance with local variables that are not
explicitly marked 'final'.  Removing the unnecessary empty comments and
'final' qualifiers makes this code more readable and more consistent
with recent JGit code.

Change-Id: I7a181432eda7e18bd32cf110d89c0efbe490c4f1
Signed-off-by: Jonathan Nieder <jrn@google.com>