This commit fixes a deadlock that can occur when the libc version
holds a lock when calling munmap. In this case we could end up calling
free() from vma_tree_delete which would in turn try to obtain the lock
in libc. To avoid the issue put any deleted vma's in a new list on the
vma module and release them on the next call to vma_tree_insert. This
should be safe as this function is not called from the memory hooks.
Signed-off-by: Nathan Hjelm <hjelmn@lanl.gov>