Escaping regex special chars (esp. '\') in delimiter matching

Uncovered by 370194b

See #444 and especially [this comment](https://github.com/jclouds/jclouds/pull/444#issuecomment-49675241)

Results on Windows (Java 6):
```
...\jclouds\jclouds> mvn -v
Apache Maven 3.2.1 (ea8b2b07643dbb1b84b6d16e1f08391b666bc1e9; 2014-02-14T12:37:52-05:00)
Maven home: C:\Program Files (x86)\Apache\maven-3.2.1\bin\..
Java version: 1.6.0_20, vendor: Sun Microsystems Inc.
Java home: C:\Program Files\Java\jdk1.6.0_20\jre
Default locale: en_GB, platform encoding: Cp1252
OS name: "windows 7", version: "6.1", arch: "amd64", family: "windows"

...\jclouds\jclouds> mvn clean install -pl blobstore

...\jclouds\jclouds> mvn clean integration-test -pl :filesystem -Plive

Results :

Tests run: 26, Failures: 0, Errors: 0, Skipped: 5

[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 23.798 s
[INFO] Finished at: 2014-07-22T10:21:26-05:00
[INFO] Final Memory: 70M/189M
[INFO] ------------------------------------------------------------------------
```