Fix console logger crash in gateway mode (#8525)

This PR also fixes config migration only
for credentials and region which are valid
and set.

Also fix implicit `state="on"` behavior

cmd/config/config_test.go

@@ -0,0 +1,44 @@
+/*
+ * MinIO Cloud Storage, (C) 2019 MinIO, Inc.
+ *
+ * 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 config
+
+import "testing"
+
+func TestValidRegion(t *testing.T) {
+	tests := []struct {
+		name    string
+		success bool
+	}{
+		{name: "us-east-1", success: true},
+		{name: "us_east", success: true},
+		{name: "helloWorld", success: true},
+		{name: "-fdslka", success: false},
+		{name: "^00[", success: false},
+		{name: "my region", success: false},
+		{name: "%%$#!", success: false},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			ok := validRegionRegex.MatchString(test.name)
+			if test.success != ok {
+				t.Errorf("Expected %t, got %t", test.success, ok)
+			}
+		})
+	}
+}