extensive orb_advert_t fixes

The calls to orb_advertise were being mishandled throughout the code.
There were ::close() calls on memory pointers, there were checks
against < 0 when it is a pointer to a object and values larger than
0x7ffffffff are valid. Some places orb_advert_t variables were
being initialized as 0 other places as -1.

The orb_advert_t type was changed to uintptr_t so the pointer value
would not be wrapped as a negative number. This was causing a failure
on ARM.

Tests for < 0 were changed to == 0 since a null pointer is the valid
representation for error, or uninitialized.

Signed-off-by: Mark Charlebois <charlebm@gmail.com>

src/modules/sdlog2/sdlog2.c

@@ -373,8 +373,7 @@ int sdlog2_main(int argc, char *argv[])
 		cmd.param1 = -1;
 		cmd.param2 = -1;
 		cmd.param3 = 1;
-		int fd = orb_advertise(ORB_ID(vehicle_command), &cmd);
-		close(fd);
+		orb_advertise(ORB_ID(vehicle_command), &cmd);
 		return 0;
 	}
 
@@ -384,8 +383,7 @@ int sdlog2_main(int argc, char *argv[])
 		cmd.param1 = -1;
 		cmd.param2 = -1;
 		cmd.param3 = 2;
-		int fd = orb_advertise(ORB_ID(vehicle_command), &cmd);
-		close(fd);
+		orb_advertise(ORB_ID(vehicle_command), &cmd);
 		return 0;
 	}