releasetools: Remove deprecated pylint options.

This option u'required-attributes' will be removed in Pylint 2.0
This option u'ignore-iface-methods' will be removed in Pylint 2.0

Test: pylint (1.6.5) no longer gives above warnings.
Change-Id: Ib07cd5aef87407260140c1fca0b11c439cbdf390
diff --git a/tools/releasetools/pylintrc b/tools/releasetools/pylintrc
index 90de1af..7b3405c 100644
--- a/tools/releasetools/pylintrc
+++ b/tools/releasetools/pylintrc
@@ -144,9 +144,6 @@
 
 [BASIC]
 
-# Required attributes for module, separated by a comma
-required-attributes=
-
 # List of builtins function names that should not be used, separated by a comma
 bad-functions=map,filter,input
 
@@ -357,10 +354,6 @@
 
 [CLASSES]
 
-# List of interface methods to ignore, separated by a comma. This is used for
-# instance to not check methods defines in Zope's Interface base class.
-ignore-iface-methods=isImplementedBy,deferred,extends,names,namesAndDescriptions,queryDescriptionFor,getBases,getDescriptionFor,getDoc,getName,getTaggedValue,getTaggedValueTags,isEqualOrExtendedBy,setTaggedValue,isImplementedByInstancesOf,adaptWith,is_implemented_by
-
 # List of method names used to declare (i.e. assign) instance attributes.
 defining-attr-methods=__init__,__new__,setUp