gitk: Fix bug where editing an existing view would cause an infinite loop

gitk: Fix bug where editing an existing view would cause an infinite loop

This fixes a bug where changing the commit range or file list for an
existing view and then clicking OK would cause gitk to go into an
infinite loop.  The problem was that newviewok was invoking reloadcommits
via "run reloadcommits", but reloadcommits wasn't explicitly returning
0, and whatever it was returning was causing dorunq to run it over
and over again.  This fixes it by making reloadcommits return 0.

Signed-off-by: Paul Mackerras <paulus@samba.org>