lguest: remove unneeded zlib.h include in example launcher

Two years ago 5bbf89fc2608 removed the horrible bzImage unpacking code.
Now it's time to remove the unneeded zlib.h include, too.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Documentation/lguest/lguest.c

@@ -34,7 +34,6 @@
 #include <sys/uio.h>
 #include <termios.h>
 #include <getopt.h>
-#include <zlib.h>
 #include <assert.h>
 #include <sched.h>
 #include <limits.h>