Add a restorecon_recursive built-in command to init.

Functionally equivalent to the restorecon -R toolbox command.
A use case is given by:
I48eaa2b9901ac8c978192c14493ba1058a089423

Also, fix error handling and documentation for restorecon command.

Change-Id: Ia7fbcc82645baf52c6bff0490d3492f458881cbb
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
diff --git a/init/keywords.h b/init/keywords.h
index f188db5..414db08 100644
--- a/init/keywords.h
+++ b/init/keywords.h
@@ -16,6 +16,7 @@
 int do_mount(int nargs, char **args);
 int do_restart(int nargs, char **args);
 int do_restorecon(int nargs, char **args);
+int do_restorecon_recursive(int nargs, char **args);
 int do_rm(int nargs, char **args);
 int do_rmdir(int nargs, char **args);
 int do_setcon(int nargs, char **args);
@@ -68,6 +69,7 @@
     KEYWORD(onrestart,   OPTION,  0, 0)
     KEYWORD(restart,     COMMAND, 1, do_restart)
     KEYWORD(restorecon,  COMMAND, 1, do_restorecon)
+    KEYWORD(restorecon_recursive,  COMMAND, 1, do_restorecon_recursive)
     KEYWORD(rm,          COMMAND, 1, do_rm)
     KEYWORD(rmdir,       COMMAND, 1, do_rmdir)
     KEYWORD(seclabel,    OPTION,  0, 0)