package/bandwidthd: add .hash file

Similar to jquery-keyboard, it seems the bandwidthd tarball on the
autobuilder is corrupt.  Fix it by adding a .hash file so it falls back to
our s.b.o mirror.

Signed-off-by: Romain Naour <romain.naour@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/bandwidthd/bandwidthd.hash

@@ -0,0 +1,2 @@
+# Locally calculated
+sha256 0270d0def6cc53c8d47d59a9dd093d51fbca1620adeef85c15e35a32010e26ab  bandwidthd-v2.0.1-auto-r11.tar.gz