Fixed IE issue

[mikeangstadt]

Fixes an IE 'Invalid Argument' exception with textareas:
Error happens, because (for whatever reason) IE temporarily converts <textarea placeholder="foo"></textarea> to <textarea placeholder="foo">foo</textarea>. This triggers a diff patch on the 'foo' innerHTML as a VTEXT node, but by the time vdom tries to set the VTEXT's value, it has been orphaned by IE.

IE throws an error whenever you try to set the nodeValue of a parentless node which exposes itself as an 'Invalid Argument' exception.

[coveralls]

Coverage remained the same at 97.531% when pulling 8aadfcb on mikeangstadt:master into 947ecf9 on Matt-Esch:master.

[panthershark]

Try always putting a value in the 3rd arg. Ex:

const attrs = { 
  "placeholder": 'dogs' 
};

h('textarea', attrs, '');