Add CVS support to Wagon SCM for site:deploy

wagon-scm + site:deploy + CVS repository combo doesn't work.

The first problem is that it tries to execute ScmWagon.mkdirs(), in which it runs:

listScmResult = scmProvider.list( baseRepository, fileSet, false, null );

This is not supported in CVS, so it fails. I'm not sure what the proper fix would be, but I worked around this by
creating the module in the repository by manually doing "cvs add <directory>", and then changed the above line to:

try

{ listScmResult = scmProvider.list( baseRepository, fileSet, false, null ); }

catch (NoSuchCommandScmException e)

{ break; // assume it's already there }

With this workaround, it then fails at the following line:

relativePath = repository.getProviderRepository().getRelativePath( baseProviderRepository );

as this method is not implemented in CvsScmProviderRepository
(I have no idea what this method does, but this method only seems to be implemented in SvnScmProviderRepository.)

Again I worked around this by changing this to:

String relativePath = null;
try

{ relativePath = repository.getProviderRepository().getRelativePath( baseProviderRepository ); }

catch (UnsupportedOperationException e)

{ // HACK }

which seems to make it work.