PPC build fix; stop using std::swap on PageAllocation/PageReservation,
this was failing on some compilers since the lack of default construction
for the m_executable/m_writable fields meant the value being swapped may
not have been fully initialized.

Patch by Gavin Barraclough <barraclough@apple.com> on 2010-12-20
* wtf/PageAllocation.h:
(WTF::PageAllocation::deallocate):
* wtf/PageBlock.h:
* wtf/PageReservation.h:
(WTF::PageReservation::deallocate):



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@74382 268f45cc-cd09-0410-ab3c-d52691b4dbfc