windows: use abspath in convert.subversion

We replace `os.path.abspath` with `util.abspath`. This should solve more "drive
capitalization" issue on Windows.

Differential Revision: https://phab.mercurial-scm.org/D11071

hgext/convert/subversion.py

@@ -164,7 +164,7 b' def geturl(path):'
         # svn.client.url_from_path() fails with local repositories
         pass
     if os.path.isdir(path):
-        path = os.path.normpath(os.path.abspath(path))
+        path = os.path.normpath(util.abspath(path))
         if pycompat.iswindows:
             path = b'/' + util.normpath(path)
         # Module URL is later compared with the repository URL returned
@@ -431,7 +431,7 b' def issvnurl(ui, url):'
             path = unicodepath.encode(fsencoding)
     except ValueError:
         proto = b'file'
-        path = os.path.abspath(url)
+        path = util.abspath(url)
         try:
             path.decode(fsencoding)
         except UnicodeDecodeError: