NSS: make colons, commas and spaces valid separators in cipher list

Fixes #7110
Closes #7115

lib/vtls/nss.c

@@ -337,7 +337,7 @@ static SECStatus set_ciphers(struct Curl_easy *data, PRFileDesc * model,
     while((*cipher) && (ISSPACE(*cipher)))
       ++cipher;
 
-    cipher_list = strchr(cipher, ',');
+    cipher_list = strpbrk(cipher, ":, ");
     if(cipher_list) {
       *cipher_list++ = '\0';
     }