Revert "v4l2: disable renegotiation"
Revert "v4l2: disable renegotiation"

This reverts commit d1b26e1d594ab2b63324e43a36330475e98cdf18.

This causes the initial negotiation to never happen if a reconfigure
event is received after gst_base_src_start_complete() but before the loop
starts.

https://bugzilla.gnome.org/show_bug.cgi?id=695981

Distrotech/gst-plugins-good,Distrotech/gst-plugins-good,Distrotech/gst-plugins-good,Distrotech/gst-plugins-good,Distrotech/gst-plugins-good