[gmime] Disable the Autocrypt injection tests if crypto isn't enabled

[Rico Tzschichholz <ricotz src gnome org>]

commit cb80feddd879947c75e40b5998dedc14e659c1d4
Author: Jeffrey Stedfast <jestedfa microsoft com>
Date:   Sat Oct 27 11:40:08 2018 -0400

    Disable the Autocrypt injection tests if crypto isn't enabled
    
    Hopefully this fixes the Travis CI builds.

 tests/test-autocrypt.c | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/tests/test-autocrypt.c b/tests/test-autocrypt.c
index 5c51a5b4..8e26aa8e 100644
--- a/tests/test-autocrypt.c
+++ b/tests/test-autocrypt.c
@@ -1066,9 +1066,11 @@ int main (int argc, char **argv)
        test_ah_message_parse ();
        testsuite_end ();
        
+#ifdef ENABLE_CRYPTO
        testsuite_start ("Autocrypt: inject headers");
        test_ah_injection ();
        testsuite_end ();
+#endif
        
        g_mime_shutdown ();