Remove bashisms, replace with POSIX constructs

This replaces double conditional brackets with single ones and gets ris
of bashisms, so that the tool should be sourcable from any POSIX shell.

Constructs like [ $foo = "$bar"* ] yield filesystem-globbing behaviour
according to POSIX. A compliant way is to use case statements.

Signed-off-by: martin f. krafft <madduck@madduck.net>

hacking/env-setup

@@ -20,14 +20,23 @@ PREFIX_PYTHONPATH="$ANSIBLE_HOME/lib"
 PREFIX_PATH="$ANSIBLE_HOME/bin"
 PREFIX_MANPATH="$ANSIBLE_HOME/docs/man"
 
-[[ "$PYTHONPATH" != "${PREFIX_PYTHONPATH}"* ]] && export PYTHONPATH=$"PREFIX_PYTHONPATH:$PYTHONPATH"
-[[ "$PATH" != "${PREFIX_PATH}"* ]] && export PATH="$PREFIX_PATH:$PATH"
+case "$PYTHONPATH" in
+  (*${PREFIX_PYTHONPATH}*) :;;
+  (*) export PYTHONPATH=$"$PREFIX_PYTHONPATH${PYTHONPATH:+:$PYTHONPATH}";;
+esac
+case "$MANPATH" in
+  (*${PREFIX_MANPATH}*) :;;
+  (*) export MANPATH=$"$PREFIX_MANPATH${MANPATH:+:$MANPATH}";;
+esac
+case "$PATH" in
+  (*${PREFIX_PATH}*) :;;
+  (*) export PATH=$"$PREFIX_PATH${PATH:+:$PATH}";;
+esac
 export ANSIBLE_LIBRARY="$ANSIBLE_HOME/library"
-[[ "$MANPATH" != "${PREFIX_MANPATH}"* ]] && export MANPATH="$PREFIX_MANPATH:$MANPATH"
 
 # Print out values unless -q is set
 
-if [ $# -eq 0 -o "$1" != "-q" ] ; then
+if [ $# -eq 0 ] || [ "$1" != "-q" ] ; then
     echo ""
     echo "Setting up Ansible to run out of checkout..."
     echo ""