SVK is a simple case to start with, as its idea of merge parents
matches git's one. When a svk:merge ticket is encountered, check each
of the listed merged revisions to see if they are in the history of
this commit; if not, then we have encountered a merge - record it.
[ew: minor formatting cleanups]
Signed-off-by: Sam Vilain <sam.vilain@catalyst.net.nz> Acked-by: Eric Wong <normalperson@yhbt.net>