convert: avoid interpreting Windows path as CVS connection strings.

CVS connection strings regexp detect colons to separate protocols from path and login. Unfortunately, Windows paths contains colons and were interpreted as rsh connection strings.

hgext/convert/cvs.py

@@ -149,7 +149,8 b' class convert_cvs(converter_source):'
             if root.startswith(":ext:"):
                 root = root[5:]
             m = re.match(r'(?:([^@:/]+)@)?([^:/]+):?(.*)', root)
-            if not m:
+            # Do not take Windows path "c:\foo\bar" for a connection strings
+            if os.path.isdir(root) or not m:
                 conntype = "local"
             else:
                 conntype = "rsh"