Merging contacts does not preserve PCPs

When merging contacts there is no option to merge/preserve PCPs (Personal Campaign Pages <- for the sake of searches in the issues database), so if the contact being merged to is not the contact who owns the PCP then the PCP page is irrevocable deleted. PCPs should be preserved across a merge. I rated this bug a critical because it involves data loss.

Lobo pointed me to the relevant places in the merge code, and the following trivial patch seems to fix the problem based on a single test I performed.