add unit test to catch issue with path to 'lmod' binary being specified using $LMOD_CMD, but 'spider' not being available in $PATH
drop fake argument to update method, use testing class variable
fix remark, drop useless self.testmods in modulestool.py unit tests
Merge pull request #873 from boegel/lmod_cmd_test

add unit test to catch bug in EB v1.11.0 related to $LMOD_CMD and spider