Remove leading/trailing single or double quotes when parsing the my.cnf
file in mysql_user and mysql_db.
Do this so that these modules parse the my.cnf file the same way that
the mysql client does.
From: http://dev.mysql.com/doc/refman/5.0/en/option-files.html
You can optionally enclose the value within single quotation marks
or double quotation marks, which is useful if the value contains a
“#” comment character.
Fixes#2405