[NCF-282]/ HAD-595112

The code that tests if a path is a url is
faulting when the url does not end in a slash
(e.g. http://thredds-tests.ucar.edu).
The code that tests if a path is a url is
faulting when the url does not end in a slash
(e.g. http://thredds-tests.ucar.edu).
CF-273]/HZY-708311

Solution was to do a null pointer test.
Added a test (tst_misc).