Replace LooseVersion

pylint is having a hard time with distutils.version in tox's virtual
envs. virtualenv uses some tricks to provide a virtual distutils
package, pylint can't cope with.

https://github.com/PyCQA/pylint/issues/73 suggests to use pkg_resources
instead. pkg_resources' version parser has some more benefits, e.g. PEP
440 conformity. But pkg_resources.parse_version() is a heavy weight solution
with reduced functionality, e.g. no access to major version.

For API_VERSION and plugin version we can use a much simpler and faster
approach.

https://fedorahosted.org/freeipa/ticket/6468

Signed-off-by: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Martin Basti <mbasti@redhat.com>
Reviewed-By: Martin Babinsky <mbabinsk@redhat.com>

ipapython/ipautil.py

@@ -1533,3 +1533,35 @@ def escape_seq(seq, *args):
     """
 
     return tuple(a.replace(seq, u'\\{}'.format(seq)) for a in args)
+
+
+class APIVersion(tuple):
+    """API version parser and handler
+
+    The class is used to parse ipapython.version.API_VERSION and plugin
+    versions.
+    """
+    __slots__ = ()
+
+    def __new__(cls, version):
+        major, dot, minor = version.partition(u'.')
+        major = int(major)
+        minor = int(minor) if dot else 0
+        return tuple.__new__(cls, (major, minor))
+
+    def __str__(self):
+        return '{}.{}'.format(*self)
+
+    def __repr__(self):
+        return "<APIVersion('{}.{}')>".format(*self)
+
+    def __getnewargs__(self):
+        return str(self)
+
+    @property
+    def major(self):
+        return self[0]
+
+    @property
+    def minor(self):
+        return self[1]