slang: disable termcap

We don't have/do it and sometimes it misdetects. Fixes:
http://autobuild.buildroot.net/results/ec9/ec9f1d7680aa50357d9a6646cef610dcaa1e8041/



Also add hash file.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>