Updates normalize_uri()

This function should not remove the trailing slash, because you may
end up getting a different HTTP response.  The new function also
allows multiple URIs as argument, and will just merge & normalize
them together. [SeeRM #7733]
Correct rspect to the correct behavior
Correctly use normalize_uri()

normalize_uri() should be used when you're joining URIs.  Because if
you're merging URIs after it's normalized, you could get double
slashes again.
This is a string, not a variable
Fix check
Fix errant use of .to_s instead of .path
Fix scrutinizer checks
Oh don't be so sensitive about it.

Fixnum vs String
Merge branch 'normalize_uri_update2' of https://github.com/wchen-r7/metasploit-framework into wchen-r7-normalize_uri_update2