Usage: repo rebase [[-i] <project>...]
Rebases the current topic branch of the specified (or all)
projects against the appropriate upstream.
Note: Interactive rebase is currently only supported when
exactly one project is specified on the command line.
Change-Id: I7376e35f27a6585149def82938c1ca99f36db2c4
Signed-off-by: Shawn O. Pearce <sop@google.com>
