installd: use correct header file.

This is a port of https://android-review.googlesource.com/52540 ,
which doesn't apply cleanly to master.

Change-Id: I2824bb7afd4e343b5dc8bed9f24002ec1dcbf07f
diff --git a/cmds/installd/commands.c b/cmds/installd/commands.c
index c272e47..a58eca8 100644
--- a/cmds/installd/commands.c
+++ b/cmds/installd/commands.c
@@ -14,7 +14,7 @@
 ** limitations under the License.
 */
 
-#include <linux/capability.h>
+#include <sys/capability.h>
 #include "installd.h"
 #include <diskusage/dirsize.h>
 #include <selinux/android.h>