[PATCH] Use SVNConstants.SVN_DIRNAME instead of ".svn" string literal

I'm working on a mixed java/dotnet project, so I need to use subversion
clients with the _svn metadata directory hack. Subclipse currently
refers to ".svn" as a string literal in a few places sprinkled
throughout the code, which makes the hack difficult to apply. The
attached patches change all such locations I found to refer to
SVNConstants.SVN_DIRNAME in svnClientAdapter, so that renaming the
metadata directory only requires a single change in the subclipse codebase.

This is my first patch posted to this list, so please let me know if
there's a more appropriate way I should be sending these changes.

Thanks,
- Marc