open-vm-tools: Add new package open-vm-tools

Add new package,
open-vm-tools is Open Virtual Machine Tools for VMware guest OS

tested: OpenWrt master and 18.06.2 (x86_64) on ESXi 6.5, 6.7

Signed-off-by: Yuhei OKAWA <tochiro.srchack@gmail.com>

utils/open-vm-tools/patches/0007-include-poll.h-instead-of-sys-poll.h.patch

@@ -0,0 +1,13 @@
+diff -urN a/lib/asyncsocket/asyncsocket.c b/lib/asyncsocket/asyncsocket.c
+--- a/lib/asyncsocket/asyncsocket.c
++++ b/lib/asyncsocket/asyncsocket.c
+@@ -69,8 +69,8 @@
+ #else
+ #include <stddef.h>
+ #include <ctype.h>
++#include <poll.h>
+ #include <sys/types.h>
+-#include <sys/poll.h>
+ #include <sys/socket.h>
+ #include <sys/un.h>
+ #include <netdb.h>