Get rid of warnings when compiled with -Wformat-security

Change-Id: Ib38b2c152474ed83be1a5716457d0b374c0e5c68
diff --git a/libnetutils/dhcpclient.c b/libnetutils/dhcpclient.c
index 45e392a..6755ba1 100644
--- a/libnetutils/dhcpclient.c
+++ b/libnetutils/dhcpclient.c
@@ -70,7 +70,7 @@
     vsnprintf(errmsg, sizeof(errmsg), fmt, ap);
     va_end(ap);
 
-    LOGD(errmsg);
+    LOGD("%s", errmsg);
 }
 
 const char *dhcp_lasterror()