git-gui: Use -M and -C when running blame.
git-gui: Use -M and -C when running blame.

Since we run blame incrementally in the background we might as well get
as much data as we can from the file.  Adding -M and -C definately makes
it take longer to compute the revision annotations, but since they are
streamed in and updated as they are discovered we'll get recent data
almost immediately anyway.

Signed-off-by: Shawn O. Pearce <f01032651c12a22b2103346ba96b3b6b231f9d3c@spearce.org>
destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git