bundler_ext - renaming namespace

BundlerExt renamed namespace, this fixes it.

Packages are on the way and will be part of the next nightly build, please merge.

```
Submitting build with: koji -c ~/.koji/katello-config build --nowait katello-thirdparty-rhel6 /tmp/tito/rubygem-bundler_ext-0.3.0-2.el6.src.rpm
Uploading srpm: /tmp/tito/rubygem-bundler_ext-0.3.0-2.el6.src.rpm
[====================================] 100% 00:00:00   9.48 KiB  11.82 KiB/sec
Created task: 19636
Task info: http://koji.katello.org/koji/taskinfo?taskID=19636
Wrote: /tmp/tito/rubygem-bundler_ext-0.3.0-2.fc16.src.rpm

Submitting build with: koji -c ~/.koji/katello-config build --nowait katello-thirdparty-fedora16 /tmp/tito/rubygem-bundler_ext-0.3.0-2.fc16.src.rpm
Uploading srpm: /tmp/tito/rubygem-bundler_ext-0.3.0-2.fc16.src.rpm
[====================================] 100% 00:00:00   9.48 KiB  12.12 KiB/sec
Created task: 19637
Task info: http://koji.katello.org/koji/taskinfo?taskID=19637
Wrote: /tmp/tito/rubygem-bundler_ext-0.3.0-2.fc17.src.rpm

Submitting build with: koji -c ~/.koji/katello-config build --nowait katello-thirdparty-fedora17 /tmp/tito/rubygem-bundler_ext-0.3.0-2.fc17.src.rpm
Uploading srpm: /tmp/tito/rubygem-bundler_ext-0.3.0-2.fc17.src.rpm
[====================================] 100% 00:00:00   9.48 KiB  12.32 KiB/sec
Created task: 19638
Task info: http://koji.katello.org/koji/taskinfo?taskID=19638
Wrote: /tmp/tito/rubygem-bundler_ext-0.3.0-2.fc18.src.rpm

Submitting build with: koji -c ~/.koji/katello-config build --nowait katello-thirdparty-fedora18 /tmp/tito/rubygem-bundler_ext-0.3.0-2.fc18.src.rpm
Uploading srpm: /tmp/tito/rubygem-bundler_ext-0.3.0-2.fc18.src.rpm
[====================================] 100% 00:00:00   9.48 KiB  12.44 KiB/sec
Created task: 19639
Task info: http://koji.katello.org/koji/taskinfo?taskID=19639
```