Improve readability by returning immediately if aPart is null.
Improve readability by returning immediately if aPart is null.

svn path=/trunk/kdepim/; revision=346310

lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi