selinux: fix memory leak in sel_make_bools

In sel_make_bools, kernel allocates memory for bool_pending_names[i]
with security_get_bools. So if we just free bool_pending_names, those
memories for bool_pending_names[i] will be leaked.

This patch resolves dozens of following kmemleak report after resuming
from suspend:
unreferenced object 0xffff88022e4c7380 (size 32):
  comm "init", pid 1, jiffies 4294677173
  backtrace:
    [<ffffffff810f76b5>] create_object+0x1a2/0x2a9
    [<ffffffff810f78bb>] kmemleak_alloc+0x26/0x4b
    [<ffffffff810ef3eb>] __kmalloc+0x18f/0x1b8
    [<ffffffff811cd511>] security_get_bools+0xd7/0x16f
    [<ffffffff811c48c0>] sel_write_load+0x12e/0x62b
    [<ffffffff810f9a39>] vfs_write+0xae/0x10b
    [<ffffffff810f9b56>] sys_write+0x4a/0x6e
    [<ffffffff81011b82>] system_call_fastpath+0x16/0x1b
    [<ffffffffffffffff>] 0xffffffffffffffff

Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>

security/selinux/selinuxfs.c

@@ -977,6 +977,8 @@ static int sel_make_bools(void)
 	u32 sid;
 
 	/* remove any existing files */
+	for (i = 0; i < bool_num; i++)
+		kfree(bool_pending_names[i]);
 	kfree(bool_pending_names);
 	kfree(bool_pending_values);
 	bool_pending_names = NULL;