Revert r54058, caused crash when adding paritcles in particle edit mode

MEM_recallocN() doesn't allocate memory when used on a null pointer.

Just revert commit since there is no real benefit to using
MEM_recallocN() in this case.

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@54108 954f8c5b-7b00-dc11-b283-0030488c597c