queue2: download mode; prevent range corruption due to race
queue2: download mode; prevent range corruption due to race

Current range was being updated in the thread performing seek, but as
no locks were kept for a short section, data flow could resume before
current range updated, so data for the new range would be accepted as
from the previous range.

Rather, range should be updated in serialized manner based on
newsegment event.

krieger-od/gstreamer,krieger-od/gstreamer,drothlis/gstreamer,justinjoy/gstreamer,drothlis/gstreamer,krichter722/gstreamer,drothlis/gstreamer,cfoch/gstreamer,centricular/gstreamer,cfoch/gstreamer,Lachann/gstreamer,jpakkane/gstreamer,StreamUtils/gstreamer,justinjoy/gstreamer,krichter722/gstreamer,lubosz/gstreamer,mrchapp/gstreamer,mparis/gstreamer,centricular/gstreamer,drothlis/gstreamer,surround-io/gstreamer,mrchapp/gstreamer,lovebug356/gstreamer,krieger-od/gstreamer,krieger-od/gstreamer,magcius/gstreamer,Distrotech/gstreamer,jpxiong/gstreamer,StreamUtils/gstreamer,collects/gstreamer,magcius/gstreamer,mparis/gstreamer,mrchapp/gstreamer,jpakkane/gstreamer,jpakkane/gstreamer,justinjoy/gstreamer,mparis/gstreamer,collects/gstreamer,ahmedammar/platform_external_gst_gstreamer,cablelabs/gstreamer,Distrotech/gstreamer,cfoch/gstreamer,ylatuya/gstreamer,jpxiong/gstreamer,ensonic/gstreamer,StreamUtils/gstreamer,mparis/gstreamer,cfoch/gstreamer,mrchapp/gstreamer,magcius/gstreamer,krichter722/gstreamer,collects/gstreamer,justinjoy/gstreamer,lovebug356/gstreamer,krieger-od/gstreamer,drothlis/gstreamer,magcius/gstreamer,surround-io/gstreamer,jpakkane/gstreamer,ahmedammar/platform_external_gst_gstreamer,collects/gstreamer,lubosz/gstreamer,cablelabs/gstreamer,Distrotech/gstreamer,ensonic/gstreamer,ylatuya/gstreamer,cablelabs/gstreamer,surround-io/gstreamer,jpxiong/gstreamer,justinjoy/gstreamer,Lachann/gstreamer,centricular/gstreamer,Distrotech/gstreamer,lovebug356/gstreamer,mparis/gstreamer,krichter722/gstreamer,ylatuya/gstreamer,ensonic/gstreamer,ensonic/gstreamer,Lachann/gstreamer,mrchapp/gstreamer,lubosz/gstreamer,cablelabs/gstreamer,shelsonjava/gstreamer,jpxiong/gstreamer,centricular/gstreamer,cablelabs/gstreamer,lovebug356/gstreamer,ylatuya/gstreamer,krichter722/gstreamer,ahmedammar/platform_external_gst_gstreamer,Lachann/gstreamer,magcius/gstreamer,shelsonjava/gstreamer,ylatuya/gstreamer,shelsonjava/gstreamer,jpxiong/gstreamer,ensonic/gstreamer,lubosz/gstreamer,cfoch/gstreamer,shelsonjava/gstreamer,StreamUtils/gstreamer,centricular/gstreamer,ahmedammar/platform_external_gst_gstreamer,shelsonjava/gstreamer,collects/gstreamer,ahmedammar/platform_external_gst_gstreamer,lovebug356/gstreamer,StreamUtils/gstreamer,Distrotech/gstreamer,lubosz/gstreamer,surround-io/gstreamer,surround-io/gstreamer,jpakkane/gstreamer,Lachann/gstreamer