Corrected issues found by "make static-checks"

And added license headers.

config/config_params.go

@@ -172,7 +172,7 @@ type Config struct {
 	IptablesLockFilePath               string            `config:"file;/run/xtables.lock"`
 	IptablesLockTimeoutSecs            time.Duration     `config:"seconds;0"`
 	IptablesLockProbeIntervalMillis    time.Duration     `config:"millis;50"`
-	FeatureDetectOverride              map[string]string `config:"keyvaluelist;"";;local"`
+	FeatureDetectOverride              map[string]string `config:"keyvaluelist;;local"`
 	IpsetsRefreshInterval              time.Duration     `config:"seconds;10"`
 	MaxIpsetSize                       int               `config:"int;1048576;non-zero"`
 	XDPRefreshInterval                 time.Duration     `config:"seconds;90"`

stringutils/parse_keyvalue_list.go

@@ -1,3 +1,18 @@
+// Copyright (c) 2020 Tigera, Inc. All rights reserved.
+// Copyright (c) 2020 Nordix Foundation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package stringutils
 
 // https://play.golang.org/p/xSEX1CAcQE
@@ -8,11 +23,10 @@ import (
 	"strings"
 )
 
-var rex = regexp.MustCompile("\\s*(\\w+)=(.*)")
+var rex = regexp.MustCompile(`\s*(\w+)=(.*)`)
 
 // ParseKeyValueList parses a comma-separated key=value list to a map.
 // Keys must contain only word characters (leading spaces ignored).
-// A valid map is always returned even when the error is != nil.
 // Spaces in the value are preserved.
 func ParseKeyValueList(param string) (map[string]string, error) {
 	res := make(map[string]string)

stringutils/parse_keyvalue_list_test.go

@@ -1,3 +1,17 @@
+// Copyright (c) 2020 Tigera, Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package stringutils_test
 
 import (