Use correct MIME media type for JSON

https://www.ietf.org/rfc/rfc4627.txt

https://github.com/rqlite/rqlite/issues/933

cluster/join.go

@@ -94,7 +94,7 @@ func join(srcIP, joinAddr, id, addr string, voter bool, tlsConfig *tls.Config, l
 		}
 
 		// Attempt to join.
-		resp, err := client.Post(fullAddr, "application-type/json", bytes.NewReader(b))
+		resp, err := client.Post(fullAddr, "application/json", bytes.NewReader(b))
 		if err != nil {
 			return "", err
 		}

disco/client.go

@@ -58,7 +58,7 @@ func (c *Client) Register(id, addr string) (*Response, error) {
 		}
 
 		c.logger.Printf("discovery client attempting registration of %s at %s", addr, url)
-		resp, err := client.Post(url, "application-type/json", bytes.NewReader(b))
+		resp, err := client.Post(url, "application/json", bytes.NewReader(b))
 		if err != nil {
 			return nil, err
 		}

system_test/helpers.go

@@ -433,7 +433,7 @@ func Remove(n *Node, addr string) error {
 	}
 
 	// Attempt to remove node from leader.
-	resp, err := http.Post("http://"+n.APIAddr+"/remove", "application-type/json", bytes.NewReader(b))
+	resp, err := http.Post("http://"+n.APIAddr+"/remove", "application/json", bytes.NewReader(b))
 	if err != nil {
 		return err
 	}
@@ -451,7 +451,7 @@ func DoJoinRequest(nodeAddr, raftID, raftAddr string, voter bool) (*http.Respons
 		return nil, err
 	}
 
-	resp, err := http.Post("http://"+nodeAddr+"/join", "application-type/json", bytes.NewReader(b))
+	resp, err := http.Post("http://"+nodeAddr+"/join", "application/json", bytes.NewReader(b))
 	if err != nil {
 		return nil, err
 	}