[SCM-798] scm:branch ignores the tagBase parameter, there is no branchBase parameter

**[Jakub Bochenski](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=jbochenski)** opened **[SCM-798](https://issues.apache.org/jira/browse/SCM-798?redirect=false)** and commented

```
[DEBUG] Configuring mojo 'org.apache.maven.plugins:maven-scm-plugin:1.9.4:branch' with basic configurator -->
[DEBUG] (f) basedir = /home/acme/gotham/common_ui
[DEBUG] (f) branch = 2.2/2.2.0
[DEBUG] (f) connectionType = connection
[DEBUG] (s) connectionUrl = scm:svn:svn+ssh://svn@svn.acme.com/repos/trunk/common_ui
[DEBUG] (f) developerConnectionUrl = scm:svn:svn+ssh://svn@svn.acme.com/repos/trunk/common_ui
[DEBUG] (f) pushChanges = true
[DEBUG] (f) remoteBranching = false
[DEBUG] (f) settings = org.apache.maven.execution.SettingsAdapter@7b300cde
[DEBUG] (f) tagBase = svn+ssh://svn@svn.acme.com/repos/branches/common_ui
[DEBUG] -- end configuration --
[INFO] Final Branch Name: '2.2/2.2.0'
[INFO] Executing: /bin/sh -c cd /home/acme/gotham/common_ui && svn --non-interactive copy --file /tmp/maven-scm-1267210601.commit . svn+ssh://svn@svn.acme.com/repos/branches/2.2/2.2.0
```

I can see this code handling `tagBase`, but there is none for `branchBase`

```
if ( !StringUtils.isEmpty( tagBase ) && repository.getProvider().equals( "svn" ) )
{
SvnScmProviderRepository svnRepo = (SvnScmProviderRepository) repository.getProviderRepository();
svnRepo.setTagBase( tagBase );
}
```

Adding a parallel handling for `branchBase` param should be trivial.

Correcting the documentation is another thing -- the `tagBase` parameter is present on the base Mojo class even though it's ignored in some goals.

---

**Affects:** 1.9.4

Start at the scm:branch goal's parameter handling and repository setup, using the shown SvnScmProviderRepository tagBase handling as the comparison point. Check the base Mojo documentation for tagBase and branch-related parameters; done means branchBase is supported for branching and the parameter documentation no longer implies tagBase applies uniformly to every goal.

Written by the indexing model from the issue text.