Update version of Chrome/Chromium's User-Agent
Update version of Chrome/Chromium's User-Agent

We identify ourselves as Chromium to other websites, but the version
we use in the User-Agent string is pretty old.  This commit updates it
to a newer version (49.0.2571.2, from Nov 22 2015).  The positive
side-effect from doing this is that Google does not bother the user
asking her to upgrade to a "newer Chrome".

dokidokivisual/midori,dokidokivisual/midori,dokidokivisual/midori,dokidokivisual/midori,dokidokivisual/midori