Stripping suburl from paths in extract_response_for_path (#15)

When accessing a server on a suburl, such as an Alfresco WebDav:

http://172.17.0.8:8080/alfresco/webdav
The file paths processed by extract_response_for_path, specifically href contains the suburl as a prefix, for instance:
/alfresco/webdav/Sites/ rather than just Sites/.
I am not sure if this is a specific problem with Alfresco WebDav, or a common issue.
Either way, the provided code fixes this issue by removing the suburl from paths, if it exists.

webdav3/client.py

@@ -16,10 +16,10 @@ from webdav3.exceptions import *
 from webdav3.urn import Urn
 
 try:
-    from urllib.parse import unquote, urlsplit
+    from urllib.parse import unquote, urlsplit, urlparse
 except ImportError:
     from urllib import unquote
-    from urlparse import urlsplit
+    from urlparse import urlsplit, urlparse
 
 __version__ = "0.2"
 log = logging.getLogger(__name__)
@@ -959,10 +959,10 @@ class WebDavXmlUtils:
         :param hostname: the server hostname.
         :return: XML object of response for the remote resource defined by path.
         """
+        prefix = urlparse(hostname).path
         try:
             tree = etree.fromstring(content)
             responses = tree.findall("{DAV:}response")
-
             n_path = Urn.normalize_path(path)
 
             for resp in responses:
@@ -970,6 +970,9 @@ class WebDavXmlUtils:
 
                 if Urn.compare_path(n_path, href) is True:
                     return resp
+                href_without_prefix = href[len(prefix):] if href.startswith(prefix) else href
+                if Urn.compare_path(n_path, href_without_prefix) is True:
+                    return resp
             raise RemoteResourceNotFound(path)
         except etree.XMLSyntaxError:
             raise MethodNotSupported(name="is_dir", server=hostname)