Merge branch '296-modulecmd-do-not-set-u-for-now' into 'master'

Resolve "modulecmd: do not set -u for now"

Closes #296

See merge request Pmodules/src!274

Pmodules/modulecmd.bash.in

@@ -6,7 +6,7 @@ unset IFS	# use default IFS
 
 shopt -s nullglob
 #set -e		# exit on error
-set -u		# Treat unset variables as an error
+#set -u		# Treat unset variables as an error
 set -o pipefail
 
 # used in some output messages only
@@ -3494,7 +3494,7 @@ if [[ -z "${subcommand}" ]]; then
 	std::die 1 "${CMD}: no sub-command specified."
 fi
 
-if [[ -z "${Subcommands[${subcommand}]}" ]]; then
+if [[ ! -v Subcommands[${subcommand}] ]]; then
 	std::die 1 "${CMD}: unknown sub-command -- ${subcommand}"
 fi