HPCC-11604 Handle escaped capitlization in makeXPathLName

HPCC-11770 introduced a regression when dealing with logical
filenames with escaped capitalization.

Signed-off-by: Jake Smith <jake.smith@lexisnexis.com>
This will ignore any paths beginning with a .

    abc::.def::ghi

would require an extra test that (e-s) == 1