[Buildroot] [git commit] package/dropbear: bump version to 2019.77

[Peter Korsgaard]

commit: https://git.buildroot.net/buildroot/commit/?id=eece7361c6c8512d57c2b440f664f0e78b4dad00
branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/master

Drop patches as they are now upstream.  Add a hash for the license file.

Verified that runtime test still works:

./support/testing/run-tests -o tests.package.test_dropbear
20:42:44 TestDropbear                             Starting
20:42:45 TestDropbear                             Building
20:44:18 TestDropbear                             Building done
20:44:24 TestDropbear                             Cleaning up