Fix problems with video debug. (#1039)
Fix problems with video debug. (#1039)

Sometimes scripts can be hard to debug and the --videoParams.debug
is your best friend. However before this fix the video wasn't stopped
correctly if an error was thrown + if you hadn't started to test
a url, the debug video also was broken.
tobli/browsertime,sitespeedio/browsertime,sitespeedio/browsertime,sitespeedio/browsertime,sitespeedio/browsertime