cleanup: go vet and golint run (#736)

* cleanup: go vet and golint run

Various cleanups trickered by go vet and golint.

* Fix tests and lowercase all errors

Lowercase all errors, some tests in kubernetes use errors from
kubernetes which do start with a capital letter.

3 files changed, 3 insertions, 3 deletions

diff --git a/middleware/rewrite/condition.go b/middleware/rewrite/condition.go
index 5bc8452a9..d4a54d44a 100644
--- a/middleware/rewrite/condition.go
+++ b/middleware/rewrite/condition.go
@@ -23,7 +23,7 @@ const (
 )
 
 func operatorError(operator string) error {
-	return fmt.Errorf("Invalid operator %v", operator)
+	return fmt.Errorf("invalid operator %v", operator)
 }
 
 func newReplacer(r *dns.Msg) replacer.Replacer {
diff --git a/middleware/rewrite/edns0.go b/middleware/rewrite/edns0.go
index 3ba214c6a..1a0685312 100644
--- a/middleware/rewrite/edns0.go
+++ b/middleware/rewrite/edns0.go
@@ -94,7 +94,7 @@ func (rule *edns0LocalRule) Rewrite(r *dns.Msg) Result {
 // newEdns0Rule creates an EDNS0 rule of the appropriate type based on the args
 func newEdns0Rule(args ...string) (Rule, error) {
 	if len(args) < 2 {
-		return nil, fmt.Errorf("Too few arguments for an EDNS0 rule")
+		return nil, fmt.Errorf("too few arguments for an EDNS0 rule")
 	}
 
 	ruleType := strings.ToLower(args[0])
diff --git a/middleware/rewrite/rewrite.go b/middleware/rewrite/rewrite.go
index 2db97b2f1..aa27c3a2a 100644
--- a/middleware/rewrite/rewrite.go
+++ b/middleware/rewrite/rewrite.go
@@ -64,7 +64,7 @@ type Rule interface {
 
 func newRule(args ...string) (Rule, error) {
 	if len(args) == 0 {
-		return nil, fmt.Errorf("No rule type specified for rewrite")
+		return nil, fmt.Errorf("no rule type specified for rewrite")
 	}
 
 	ruleType := strings.ToLower(args[0])