testing: Disable leak detective when generating CRLs

GnuTLS, which can get loaded by the curl plugin, does not properly cleanup
some allocated memory when deinitializing.  This causes invalid frees if
leak detective is active.  Other invalid frees are related to time
conversions (tzset).

References #1382.

testing/hosts/winnetou/etc/openssl/generate-crl

@@ -14,6 +14,10 @@
 # or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 # for more details.
 
+# libgnutls, if pulled in by libcurl, does not properly cleanup all memory,
+# which causes invalid frees during shutdown when leak detective is used
+export LEAK_DETECTIVE_DISABLE=1
+
 export COMMON_NAME=strongSwan
 
 ROOT=/var/www