tests/hd-geo-test.c: Remove unused test_image variable

Remove unused variable test_image; this silences a clang warning.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

tests/hd-geo-test.c

@@ -22,8 +22,6 @@
 #include "qemu-common.h"
 #include "libqtest.h"
 
-static const char test_image[] = "/tmp/qtest.XXXXXX";
-
 static char *create_test_img(int secs)
 {
     char *template = strdup("/tmp/qtest.XXXXXX");