Add the commands rm and rmdir to init.

rm only removes a single non-directory directory entry (no -r support)
rmdir removes a single empty directory

Change-Id: I49702b02ba98a177027b126268c2c2846f968195
diff --git a/init/builtins.c b/init/builtins.c
index 915c5aa..490ad48 100644
--- a/init/builtins.c
+++ b/init/builtins.c
@@ -485,6 +485,16 @@
     return symlink(args[1], args[2]);
 }
 
+int do_rm(int nargs, char **args)
+{
+    return unlink(args[1]);
+}
+
+int do_rmdir(int nargs, char **args)
+{
+    return rmdir(args[1]);
+}
+
 int do_sysclktz(int nargs, char **args)
 {
     struct timezone tz;