Follow redirects on PUT

Inspired by https://github.com/bitfireAT/davdroid/issues/414

CHANGELOG.rst

@@ -14,6 +14,9 @@ Version 0.4.2
 
 *yet to be released*
 
+- Vdirsyncer now respects redirects when uploading and updating items. This
+  might fix issues with Zimbra.
+
 Version 0.4.1
 =============
 

vdirsyncer/storage/dav.py

@@ -427,6 +427,7 @@ class DavStorage(Storage):
             headers=headers
         )
         etag = response.headers.get('etag', None)
+        href = self._normalize_href(response.url)
         if not etag:
             item2, etag = self.get(href)
             assert item2.uid == item.uid