trim values from envrionment files (#13991)

trim values to remove any spaces, newlines
from the files while importing credentials
and other values.

cmd/common-main_test.go

@@ -24,6 +24,49 @@ import (
 	"testing"
 )
 
+func Test_readFromSecret(t *testing.T) {
+	testCases := []struct {
+		content       string
+		expectedErr   bool
+		expectedValue string
+	}{
+		{
+			"value\n",
+			false,
+			"value",
+		},
+		{
+			" \t\n Hello, Gophers \n\t\r\n",
+			false,
+			"Hello, Gophers",
+		},
+	}
+
+	for _, testCase := range testCases {
+		testCase := testCase
+		t.Run("", func(t *testing.T) {
+			tmpfile, err := ioutil.TempFile("", "testfile")
+			if err != nil {
+				t.Error(err)
+			}
+			tmpfile.WriteString(testCase.content)
+			tmpfile.Sync()
+			tmpfile.Close()
+
+			value, err := readFromSecret(tmpfile.Name())
+			if err != nil && !testCase.expectedErr {
+				t.Error(err)
+			}
+			if err == nil && testCase.expectedErr {
+				t.Error(errors.New("expected error, found success"))
+			}
+			if value != testCase.expectedValue {
+				t.Errorf("Expected %s, got %s", testCase.expectedValue, value)
+			}
+		})
+	}
+}
+
 func Test_minioEnvironFromFile(t *testing.T) {
 	testCases := []struct {
 		content      string