fix text for renaming defaultText to placeholder

Author: atlanteh

test/index.test.js

@@ -223,15 +223,15 @@ describe('DatePicker:', () => {
     expect(datePicker.onPressDate).to.throw(Error);
   });
 
-  it('getTitle - with defaultText', () => {
-    const defaultText = 'Please pick a date';
-    const wrapper = shallow(<DatePicker defaultText={defaultText} />);
+  it('getTitle - with placeholder', () => {
+    const placeholder = 'Please pick a date';
+    const wrapper = shallow(<DatePicker placeholder={placeholder} />);
     const datePicker = wrapper.instance();
 
-    expect(datePicker.getTitle()).to.equal(defaultText);
+    expect(datePicker.getTitle()).to.equal(placeholder);
   });
 
-  it('getTitle - without defaultText', () => {
+  it('getTitle - without placeholder', () => {
     const wrapper = shallow(<DatePicker date="2016-06-04" />);
     const datePicker = wrapper.instance();