message: replace DateTimePicker div wrapper with Fragment
diff: -import React, { Component } from 'react';
  +import React, { Component, Fragment } from 'react';
  import PropTypes from 'prop-types';
  import { withStyles } from 'material-ui';
  @@ -106,7 +106,7 @@ export class DateTimePicker extends Component {
  } = this.props;
  return (
  - <div>
  + <Fragment>
  <DatetimePickerHeader
  date={date}
  openView={openView}
  @@ -173,7 +173,7 @@ export class DateTimePicker extends Component {
  utils={utils}
  />
  </View>
  - </div>
  + </Fragment>
  );
  }
  }
  