mapping properties have inconsistent behavior

[huhlig]

Original Ticket: https://github.com/mojohaus/rpm-maven-plugin/issues/8

Currently there are 4 default parameters: defaultFilemode, defaultDirmode, defaultUsername, defaultGroupname

However there are 3 overrideable parameters: filemode, username, groupname

The use of filemode is inconsistent and prone to causing issues.

Example:

When I am building an rpm for an application I am setting most files as 444 permissions and the directory as 555. However if I override this with filemode then this will also alter the directory permission to become that as well which is an undesirable behavior. filemode should not override defaultDirmode. This should be overridden by 'dirmode' property on a per mapping basis.