Duration not refreshing after setSrc when using flash

[fvianello]

Hi @johndyer,

If i load a video in IE8 using flash and then change the src using the js method the flash player doesn't refresh the duration variable so it keep the duration of the first video played.

I found that commenting the line where you check if duration is equal to zero the problem is fixed but I don't know if this could break something.

https://github.com/johndyer/mediaelement/blob/master/src/flash/htmlelements/VideoElement.as#L232

[rounce]

more correct fix: #1127
Your solution breaks seek.