ipalib.parameters: Handle 0-prefixed octal format of ints

In Python 2, numbers prfixed with '0' are parsed as octal,
e.g. '020' -> 16. In Python 3, the prefix is '0o'.

Handle the old syntax for IPA's parameter conversion to keep
backwards compatibility.

Reviewed-By: Tomas Babej <tbabej@redhat.com>

ipalib/parameters.py

@@ -1072,6 +1072,9 @@ class Int(Number):
         if type(value) is unicode:
             if u'.' in value:
                 return int(float(value))
+            if six.PY3 and re.match('0[0-9]+', value):
+                # 0-prefixed octal format
+                return int(value, 8)
             return int(value, 0)
 
         raise ValueError(value)