Fix regression in b894280a.

Code calls list_find_first to search in resv_list whether the requested
name for the new reservation already exists. If it exists, resv_ptr is
set with the pointer to the existing reservation. Then the code goto
bad_parse label and xfreed that resv_ptr, thus corrupting the list data
by freeing the existing reservation. This is fixed by only freeing memory on the
new local resv_ptr instead of always freeing memory.  xfree is also not
sufficient for freeing the memory, we needed to call _del_resv_rec() or we would
leak the memory we had transferred from the resv_desc_ptr.  This also involved
NULLing out the other variables freed after bad_parse, or you would get
double frees.

Bug 3558.