memindex: avoid busy loop when doing EXACT lookup
memindex: avoid busy loop when doing EXACT lookup

Fixes #610367.

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