detect/port: handle single port that is range too

detect/port: handle single port that is range too

If a port point is single but later on also a part of a range, it ends
up only creating the port groups for single points and not the range.
Fix it by adding the port next to current single one to unique points
and marking it a range port.

Bug 6843

(cherry picked from commit 632ca75dd3f49bee865f047cc5336870f3a431d2)