dev-python/twisted: bump to 19.10.0

dev-python/twisted: bump to 19.10.0

* Remove net-misc/openssh version constraint
* dev-python/bcrypt is now in DEPEND
* Drop all patches which are no longer required
* Clean python_test() per previous comment

Package is still not compatible with py3.8 but is very close. We should see full
support soon. Most tests pass with py3.8. Additionally, dev-python/automat will
require a bump to >=0.8.0 in order to support py3.8 within twisted.

Bug: https://bugs.gentoo.org/661258
Bug: https://bugs.gentoo.org/662340
Bug: https://bugs.gentoo.org/677226
Bug: https://bugs.gentoo.org/690790
Bug: https://bugs.gentoo.org/683910

Signed-off-by: Aaron Bauman <bman@gentoo.org>