[select] doesn't show initial selection when values are boolean type.

[martinraie]

Describe the bug
MdcSelect doesn't show initial selection when values are boolean type.

To Reproduce
Steps to reproduce the behavior:

1. Add following mdc-select in template:

  <mdc-select name="selectSmth" [(ngModel)]="selectedValue">
    <mdc-menu>
      <mdc-list>
        <mdc-list-item value="true">Positive</mdc-list-item>
        <mdc-list-item value="false">Negative</mdc-list-item>
      </mdc-list>
    </mdc-menu>
  </mdc-select>

2. Add boolean type initial value to component:

selectedValue = false;

3. When opening the page I expect select's value to be "Negative" but it is blank instead.

Expected behavior
I expect "Negative" (value false) to be selected as initial value in the select box.

What Angular MDC version are you using?
5.1.1

What OS are you using?:
Ubuntu 18.04

What browser(s) is this bug affecting?:
Chrome

Additional context
It worked with MDC 3.2.1 and it works with vanilla Angular select/option

[trimox]

@martinraie Thanks for reporting and including steps to reproduce. Will review..

[martinraie]

Tried it also with square brackets like this:

        <mdc-list-item [value]="true">Positive</mdc-list-item>
        <mdc-list-item [value]="false">Negative</mdc-list-item>

Then the true option started to work but false still doesn't work.