Fix some tests

- Some tests were failing due to a bad string
- This commit modifies the strings to make the tests succeeded

Author: Franck Rupin

ovs/datapath_test.go

@@ -567,15 +567,15 @@ func TestDelCTLimits(t *testing.T) {
 			},
 			zones:    []uint64{4, 3},
 			dpName:   "",
-			err:      "datapath name is missing",
+			err:      "datapath name argument is mandatory",
 			testCase: handleError,
 		},
 		{
 			desc:     "Test del limit with empty paramaters",
 			dp:       NewDataPathService(),
 			zones:    []uint64{},
 			dpName:   "",
-			err:      "datapath name is missing",
+			err:      "datapath name argument is mandatory",
 			testCase: handleError,
 		},
 	}
@@ -625,15 +625,15 @@ func TestDelCTLimitsWithBinary(t *testing.T) {
 			dp:       NewDataPathService(),
 			zones:    []uint64{4, 3},
 			dpName:   "",
-			err:      "datapath name is missing",
+			err:      "datapath name argument is mandatory",
 			testCase: handleError,
 		},
 		{
 			desc:     "Test del limit with empty paramaters",
 			dp:       NewDataPathService(),
 			zones:    []uint64{},
 			dpName:   "",
-			err:      "datapath name is missing",
+			err:      "datapath name argument is mandatory",
 			testCase: handleError,
 		},
 	}