ifnet/tests: fix GCC 5 warning about possible misuse of logical not

With GCC 5, -Wlogical-not-parentheses is enabled by -Wall and warns
about suspicious code like:

  int a;
  ...
  if (!a > 1) { ... }

Fix the following warning:

test_all.c: In function ‘test_is_static’:
test_all.c:114:32: warning: logical not is only applied to the left hand side of comparison [-Wlogical-not-parentheses]
  ASSERT (!is_static_ip6 ("eth0") == TRUE, "is static",
                                  ^

1 files changed, 1 insertions, 1 deletions

diff --git a/src/settings/plugins/ifnet/tests/test_all.c b/src/settings/plugins/ifnet/tests/test_all.c
index 76ed0c7d62..55e7e283e5 100644
--- a/src/settings/plugins/ifnet/tests/test_all.c
+++ b/src/settings/plugins/ifnet/tests/test_all.c
@@ -111,7 +111,7 @@ test_is_static (void)
 		"a dhcp interface is recognized as static");
 	ASSERT (is_static_ip4 ("eth0") == TRUE, "is static",
 		"a static interface is recognized as dhcp");
-	ASSERT (!is_static_ip6 ("eth0") == TRUE, "is static",
+	ASSERT (is_static_ip6 ("eth0") == FALSE, "is static",
 		"a dhcp interface is recognized as static");
 }