Rename Contact parameter select 'method' to 'methods'

According RFC3840 the correct name of the parameter is 'methods',
not 'method'.

Reported by Daniel-Constantin Mierla

select_core.c

@@ -236,8 +236,8 @@ int select_contact_params_spec(str* res, select_t* s, struct sip_msg* msg)
 		TEST_RET_res_body(c->q);
 	case SEL_PARAM_EXPIRES:
 		TEST_RET_res_body(c->expires);
-	case SEL_PARAM_METHOD:
-		TEST_RET_res_body(c->method);
+	case SEL_PARAM_METHODS:
+		TEST_RET_res_body(c->methods);
 	case SEL_PARAM_RECEIVED:
 		TEST_RET_res_body(c->received);
 	case SEL_PARAM_INSTANCE:

select_core.h

@@ -41,7 +41,7 @@
 
 enum {
 	SEL_PARAM_TAG, 
-	SEL_PARAM_Q, SEL_PARAM_EXPIRES, SEL_PARAM_METHOD, SEL_PARAM_RECEIVED, SEL_PARAM_INSTANCE, 
+	SEL_PARAM_Q, SEL_PARAM_EXPIRES, SEL_PARAM_METHODS, SEL_PARAM_RECEIVED, SEL_PARAM_INSTANCE, 
 	SEL_PARAM_BRANCH, SEL_PARAM_RPORT, SEL_PARAM_I, SEL_PARAM_ALIAS
        };
 
@@ -251,7 +251,7 @@ static select_row_t select_core[] = {
 	{ select_contact, SEL_PARAM_STR, STR_STATIC_INIT("name"), select_contact_name, 0}, 
 	{ select_contact, SEL_PARAM_STR, STR_STATIC_INIT("q"), select_contact_params_spec, DIVERSION | SEL_PARAM_Q}, 
 	{ select_contact, SEL_PARAM_STR, STR_STATIC_INIT("expires"), select_contact_params_spec, DIVERSION | SEL_PARAM_EXPIRES}, 
-	{ select_contact, SEL_PARAM_STR, STR_STATIC_INIT("method"), select_contact_params_spec, DIVERSION | SEL_PARAM_METHOD}, 
+	{ select_contact, SEL_PARAM_STR, STR_STATIC_INIT("methods"), select_contact_params_spec, DIVERSION | SEL_PARAM_METHODS}, 
 	{ select_contact, SEL_PARAM_STR, STR_STATIC_INIT("received"), select_contact_params_spec, DIVERSION | SEL_PARAM_RECEIVED}, 
 	{ select_contact, SEL_PARAM_STR, STR_STATIC_INIT("instance"), select_contact_params_spec, DIVERSION | SEL_PARAM_INSTANCE}, 	
 	{ select_contact, SEL_PARAM_STR, STR_STATIC_INIT("params"), select_contact_params, CONSUME_NEXT_STR},