Sometimes we get Maps URL containing a zoom level as a float (17.5z and
not 17z) but this doesn’t work with our current onebox implementation.
While Google accepts those float zoom levels, it removes automatically
the floating part in the URL (thus when visiting a Maps URL containing
17.5z, the URL will be rewritten shortly after as 17z). When putting a
float zoom level in an embedded URL, this actually breaks (Maps API
returns a 400 error).
This patch addresses the issue by allowing the onebox engine to match on
a zoom level expressed as a float but we only keep the integer part thus
rendering properly maps.