LP 1473054: No-op Checkin Should Not Float a Floating Copy.

LP 1473054: No-op Checkin Should Not Float a Floating Copy.

Prior to this patch, a no-op checkin would not check if a copy should
float using the evergreen.can_float() function.  It would simply float
the copy to the org_unit where the checkin happened if the copy had a
float value set.

This commit changes the behavior of no-op checkin to never float a
floating copy, thus considering floating as another operation that
should be skipped on a no-op checkin.

Signed-off-by: Jason Stephenson <jason@sigio.com>