Simplify logic in router matcher

cppcheck takes a little issue with this logic having some redundancies
in it.  Regardless of that, it's kind of hard to read;  Rearrange the
logic so it's easier to read and add comments.

Tested: Redfish service validator passes.

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: I0251ceb511e1bc62260b68c430b272d02b90fcb7