[CodeComplete] Penalize inherited ObjC properties for auto-completion

Summary:
Similar to auto-completion for ObjC methods, inherited properties
should be penalized / direct class and category properties should
be prioritized.

Note that currently, the penalty for using a result from a base class
(CCD_InBaseClass) is equal to the penalty for using a method as a
property (CCD_MethodAsProperty).

Reviewers: jkorous, sammccall, akyrtzi, arphaman, benlangmuir

Reviewed By: sammccall, akyrtzi

Subscribers: arphaman, cfe-commits

Differential Revision: https://reviews.llvm.org/D53900

llvm-svn: 347352