Add swapon_all to init's builtin commands

For enabling swap devices found in the fstab file

Change-Id: Iec4fd4d208df3d7a161a90d95f8606e8b516334a
diff --git a/init/keywords.h b/init/keywords.h
index f147506..5a44df3 100644
--- a/init/keywords.h
+++ b/init/keywords.h
@@ -27,6 +27,7 @@
 int do_setsebool(int nargs, char **args);
 int do_start(int nargs, char **args);
 int do_stop(int nargs, char **args);
+int do_swapon_all(int nargs, char **args);
 int do_trigger(int nargs, char **args);
 int do_symlink(int nargs, char **args);
 int do_sysclktz(int nargs, char **args);
@@ -84,6 +85,7 @@
     KEYWORD(socket,      OPTION,  0, 0)
     KEYWORD(start,       COMMAND, 1, do_start)
     KEYWORD(stop,        COMMAND, 1, do_stop)
+    KEYWORD(swapon_all,  COMMAND, 1, do_swapon_all)
     KEYWORD(trigger,     COMMAND, 1, do_trigger)
     KEYWORD(symlink,     COMMAND, 1, do_symlink)
     KEYWORD(sysclktz,    COMMAND, 1, do_sysclktz)