Only update submodules when recursive is true

##### Issue Type:

“Bug Report” /  “Bugfix Pull Request”

##### Ansible Version:

ansible 1.6 (devel a5e7492c4f) last updated 2014/04/15 21:12:13 (GMT -400)

##### Environment:

Ubuntu 12.04

##### Summary:

Setting the git recursive parameter to no does not stop a repo with submodules from having all of the submodules cloned. While the `--recursive` flag is added to the clone command , the `main` function calls `switch_version` which automatically runs `submodule_update` without checking the recursive parameter.

This pull request adds that logic that only updates the submodules when the recursive parameter is set.

##### Steps To Reproduce:

With a git repo with submodules,  run 

`git: repo=reponame dest=place/to/put/it recursive=no`

##### Expected Results:

I expect my base module to be cloned / pulled, but for none of the submodules contents to be present. The path that the submodules point to should exist, but that should bot have the content from their repos

##### Actual Results:

_Before PR_:
All submodules are fully updated, with all contents present.

_After PR_
Expected Result