Sorting the file systems now
Merge pull request #153 from tzakian/auxio_env_sort

We currently use printchplenv --make to determine the path for the gen directory. Since we were not sorting the names in the environment variable for CHPL_AUX_FILESYS we wound up viewing CHPL_AUX_FILESYS="hdfs curl" as different from CHPL_AUX_FILESYS="curl hdfs".

This fixes this problem by first sorting the string before adding the underscores for the path.

Reviewed by @kyleb