Fix an allocation bug that could occur on non-LP64 platforms.
match_edges_out is an array of integers representing the
edges of the graph (where vertices are ints), with two ints
for every edge. The previous code allocated enough space
for num_dges * sizeof(int*), which happens to be the same
as num_edges * 2 * sizeof(int) on LP64 platforms, but would
be wrong on all other platforms.
Fixes: CID 1417754
Signed-off-by: Brian Barrett <bbarrett@amazon.com>