HPCC-11428 Make xsd file names consistent

     - Ensure that all references to environment.xsd
       use the same file name and case.

Signed-off-by: Gleb Aronsky <gleb.aronsky@lexisnexis.com>
Merge pull request #5869 from garonsky/HPCC-11428_Change_Environment_to_environment_for_xsds

HPCC-11428 Make xsd file names consistent

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>