rebase: Fix the detection of fast-forwarding of the current branch to upstream.
rebase: Fix the detection of fast-forwarding of the current branch to upstream.

Previously, a rebasing operation with on a branch that is just tracking
an upstream branch would output a confusing "Nothing to do" due to no
patches being given to git-am.

The test brings the behaviour back into line with that of just before
e646c9c8c0aa995eac284ea0a2117add19c4461c.

Signed-off-by: Robert Shearman <7e09c9d3e96378bf549fc283fd6e1e5b7014cc33@codeweavers.com>
Signed-off-by: Junio C Hamano <dc50d1021234060e53ec42a77d526afa2fe07479@cox.net>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git