Alter escaping in postgresql::config::afterservice

This allows non-standard users (pe-postgres) to change passwords. Also
added a function to do escaping of the password, added system tests
and rspec tests for the function.
reverting path on exec
amending the unless on the exec for quoting also
modified tests
Release 2.4.1

This updates the Modulefile and Changelog for release 2.4.1.

Signed-off-by: Ken Barber <ken@bob.sh>
Merge pull request #228 from kbarber/release-241

Release 2.4.1
Add README entry for postgresql::plperl
Fix postgresql::plperl documentation
Merge pull request #229 from mcanevet/plperl

Add README entry for postgresql::plperl
Merge pull request #218 from fiddyspence/set_postgres_postgrespw

Alter escaping in postgresql::config::afterservice
Rewrite the fact to be more concise and expand testing.