Fix linter warnings

Ignore dups in test.
Also some minor fixes.

.golangci.yml

@@ -16,3 +16,8 @@ issues:
   exclude-use-default: false
   max-per-linter: 0
   max-same-issues: 50
+
+  exclude-rules:
+    - path: _test\.go
+      linters:
+        - dupl

candidate.go

@@ -146,7 +146,7 @@ func (c *Candidate) recvLoop() {
 			}
 			// Explicitly copy raw buffer so Message can own the memory.
 			copy(m.Raw, buffer[:n])
-			if err := m.Decode(); err != nil {
+			if err = m.Decode(); err != nil {
 				log.Warnf("Failed to handle decode ICE from %s to %s: %v", c.addr(), srcAddr, err)
 				continue
 			}

url.go

@@ -155,13 +155,13 @@ func ParseURL(raw string) (*URL, error) {
 	switch {
 	case u.Scheme == SchemeTypeSTUN:
 		qArgs, err := url.ParseQuery(rawParts.RawQuery)
-		if err != nil || (err == nil && len(qArgs) > 0) {
+		if err != nil || len(qArgs) > 0 {
 			return nil, ErrSTUNQuery
 		}
 		u.Proto = ProtoTypeUDP
 	case u.Scheme == SchemeTypeSTUNS:
 		qArgs, err := url.ParseQuery(rawParts.RawQuery)
-		if err != nil || (err == nil && len(qArgs) > 0) {
+		if err != nil || len(qArgs) > 0 {
 			return nil, ErrSTUNQuery
 		}
 		u.Proto = ProtoTypeTCP