Replace cutils/log.h and rationalize log/log.h and android/log.h

- cutils/log.h treat as deprecated and lead by example
- android/log.h to be used instead of log/log.h if possible
- add system includes that are assumed as side effects
- define LOG_TAG first

Test: compile
Bug: 31289077
Bug: 30465923
Change-Id: I8d99b24c333578c9b5aa9f2a01324bd0bba268dd
diff --git a/cmds/ip-up-vpn/ip-up-vpn.c b/cmds/ip-up-vpn/ip-up-vpn.c
index 5c566fc..3b8955b 100644
--- a/cmds/ip-up-vpn/ip-up-vpn.c
+++ b/cmds/ip-up-vpn/ip-up-vpn.c
@@ -29,7 +29,7 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 
-#include <android/log.h>
+#include <log/log.h>
 
 #define DIR "/data/misc/vpn/"