jquery-keyboard: add .hash file

jquery-keyboard: add .hash file

Fixes:
http://autobuild.buildroot.org/results/d75/d7500f7e063b94e9991bacfd1df9fa5aa1967db0/
http://autobuild.buildroot.org/results/f48/f485ee75ec4c9b87f17b8b8dc1898590045474b4/

For some odd reason, the file on the autobuilder ended up getting prefixed
by these 7 bytes:

00000000  31 62 30 31 61 0d 0a 1f  8b 08 00 00 00 00 00 00  |1b01a...........|

And suffixed by these 7 bytes:

0001b020  00 0d 0a 30 0d 0a 0d 0a

Which then caused gzip to fail to extract it. It is not clear to me how this
could happen (Github glitz?  It looks suspiciously like HTTP/1.1 chunked
encoding going wrong, E.G.  0x1b01a = 110618 = tarball size) - but adding a
.hash file fixes it as the corruption gets detected and we fall back to our
s.b.o mirror.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>