libstrophe: add .hash file
Fixes:
http://autobuild.buildroot.org/results/847/847813211e29bdf8b986696ba5fd5d561e66ca2c/
http://autobuild.buildroot.org/results/b42/b420d52c49ab228f9599f9e03bb55ad3e4dd0fda/
Similar to jquery-keyboard, it seems the libstrophe 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: Peter Korsgaard <peter@korsgaard.com>
Peter Korsgaard