BUG/MEDIUM: pattern: some entries are not deleted with case insensitive match

BUG/MEDIUM: pattern: some entries are not deleted with case insensitive match

ACL or map entries are not deleted with the command "del acl" or "del map"
if the case insentive flag is set.

This is because the the case insensitive string are stored in a list and the
default delete function associated with string looks in a tree. I add a check
of the case insensitive flag and execute the delete function for lists if it
is set.

This patch must be backported in 1.5 version.