BUG/MEDIUM: ssl/crt-list: correctly insert crt-list line if crt already loaded

In issue #940, it was reported that the crt-list does not work correctly
anymore. Indeed when inserting a crt-list line which use a certificate
previously seen in the crt-list, this one won't be inserted in the SNI
list and will be silently ignored.

This bug was introduced by commit  47da821 "MEDIUM: ssl: emulates the
multi-cert bundles in the crtlist".

This patch also includes a reg-test which tests this issue.

This bugfix must be backported in 2.3.
diff --git a/reg-tests/ssl/simple.crt-list b/reg-tests/ssl/simple.crt-list
new file mode 100644
index 0000000..9ffacb4
--- /dev/null
+++ b/reg-tests/ssl/simple.crt-list
@@ -0,0 +1,5 @@
+common.pem record1.bug940.domain.tld
+common.pem record2.bug940.domain.tld
+ecdsa.pem record3.bug940.domain.tld
+ecdsa.pem record4.bug940.domain.tld
+