ae4768654e
Covers the case when nothing has changed except the commit
of the rebased patch set. This is possible when a patch set is
rebased on target branch.
With this patch, when PS1 is rebased (without modification) to PS2
the Verified+1 and Code-Review+2 will be copied since PS1 and PS2 are
effectively the same change with different commits.
----- (B) ----- (B+M) ----- (B+M-M)
\ \
----- (PS1) ----- (PS2)
Change-Id: I6a8ebd3c83ca6167cfc826267a057a871c752ff6