Fix issue 1782 don't do url2pathname conversion for urls

And only replace os-dependent path separators when necessary

hgext/convert/subversion.py

@@ -153,10 +153,12 b" protomap = {'http': httpcheck,"
 def issvnurl(url):
     try:
         proto, path = url.split('://', 1)
+        if proto == 'file':
         path = urllib.url2pathname(path)
     except ValueError:
         proto = 'file'
         path = os.path.abspath(url)
+    if proto == 'file':
     path = path.replace(os.sep, '/')
     check = protomap.get(proto, lambda p, p2: False)
     while '/' in path: