init: more header cleanup

Remove includes of "log.h" that really want <android-base/logging.h>
Fix header include order
Remove headers included in .cpp files that their associated .h already includes
Remove some unused headers

Test: boot bullhead
Change-Id: I2b415adfe86a5c8bbe4fb1ebc53c7b0ee2253824
diff --git a/init/keychords.cpp b/init/keychords.cpp
index 5801ea8..c572cee 100644
--- a/init/keychords.cpp
+++ b/init/keychords.cpp
@@ -14,19 +14,17 @@
  * limitations under the License.
  */
 
-#include <errno.h>
 #include <fcntl.h>
 #include <stdlib.h>
-#include <string.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <linux/keychord.h>
 #include <unistd.h>
 
+#include <android-base/logging.h>
 #include <android-base/properties.h>
 
 #include "init.h"
-#include "log.h"
 #include "service.h"
 
 static struct input_keychord *keychords = 0;