REGTESTS: fix sni used in http_reuse_conn_hash for libressl 3.3.0

libressl 3.3.0 is stricter on the sni field and fails if it contains
illegal characters such as the underscore. Replace sni field with proper
name to pass the test on the CI environment.

reg-tests/connection/http_reuse_conn_hash.vtc

@@ -49,25 +49,25 @@ haproxy h1 -conf {
 client c_sni -connect ${h1_feS_sni_sock} {
 	# first request
 	txreq \
-	  -hdr "x-sni: custom_sni"
+	  -hdr "x-sni: www.custom.com"
 	rxresp
 	expect resp.http.http_first_request == "1"
 
 	# second request with same sni, connection must be reused
 	txreq \
-	  -hdr "x-sni: custom_sni"
+	  -hdr "x-sni: www.custom.com"
 	rxresp
 	expect resp.http.http_first_request == "0"
 
 	# third request with a different sni, a new connection must be used
 	txreq \
-	  -hdr "x-sni: custom_sni_2"
+	  -hdr "x-sni: www.custom2.com"
 	rxresp
 	expect resp.http.http_first_request == "1"
 
 	# fourth request, reuse sni2
 	txreq \
-	  -hdr "x-sni: custom_sni_2"
+	  -hdr "x-sni: www.custom2.com"
 	rxresp
 	expect resp.http.http_first_request == "0"
 } -run