adb: remove obsolete adb.connected system property.

This was used for adb networking, which no longer exists.
This code also failed when adb was not running as root.

Change-Id: Ied86fb1930094d5ae5009684d25e15385fd31d03
Signed-off-by: Mike Lockwood <lockwood@android.com>

adb/adb.c

@@ -144,9 +144,6 @@ void put_apacket(apacket *p)
 void handle_online(void)
 {
     D("adb: online\n");
-#if !ADB_HOST
-    property_set("adb.connected","1");
-#endif
 }
 
 void handle_offline(atransport *t)
@@ -154,9 +151,6 @@ void handle_offline(atransport *t)
     D("adb: offline\n");
     //Close the associated usb
     run_transport_disconnects(t);
-#if !ADB_HOST
-    property_set("adb.connected","");
-#endif
 }
 
 #if TRACE_PACKETS