builddeb: ignore errors about find not finding files stable

builddeb: ignore errors about find not finding files

The debuild command may output less files than we explicitly list so let's not
error out if none exist.

--- a/contrib/builddeb	Sat Apr 16 12:42:53 2016 -0700
+++ b/contrib/builddeb	Fri Apr 15 14:27:42 2016 -0700
@@ -84,7 +84,7 @@
     OUTPUTDIR=${OUTPUTDIR:=packages/$DISTID-$CODENAME}
     mkdir -p "$OUTPUTDIR"
     find ../mercurial*.deb ../mercurial_*.build ../mercurial_*.changes \
-          -type f -newer $control -print0 | \
+          -type f -newer $control -print0 2>/dev/null | \
       xargs -Inarf -0 mv narf "$OUTPUTDIR"
     echo "Built packages for $debver:"
     find "$OUTPUTDIR" -type f -newer $control -name '*.deb'