python27Packages.application: 2.7.0 -> 2.8.0 and fix build; python27Packages.python-otr: mark as broken

[bhipple]

The build is currently broken due to failure to build darcs to fetch the src
package. The homepage is already their GitHub repo, and it appears to be the
active src of development anyways. See #83718

I came across this while debugging this failure:
https://hydra.nixos.org/build/115510612

Note that the application dependency does succeed on Hydra, because it's
already on local disk in Hydra's store, but I cannot rebuild locally because it
has prefer local builds.
https://hydra.nixos.org/build/115512559

This package is not reproducible on 20.03 or buildable outside of Hydra, so I
intend to backport the fix.

CC @NixOS/nixos-release-managers

ZHF: #80379

Motivation for this change

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

[bhipple]

2 package updated:
python2.7-python-application (2.7.0 → 2.8.0) python2.7-python-otr

1 package failed to build:
python27Packages.python-otr

1 package built:
python27Packages.application

Note that python-otr is the package I'm trying to fix for ZHF, but without this PR I can't fetch and build its dependencies.

[bhipple]

Looks like the python-otr package is a known issue with python2 packaging:
#74619

[bhipple]

1 package updated:
python2.7-python-application (2.7.0 → 2.8.0)

[1 built, 0.0 MiB DL]
1 package built:
python27Packages.application

Looks "better" now.

[bhipple]

This is used by exactly 1 other package in all of NixPkgs, and that package actually asserts that we need 2.8.0:
https://github.com/AGProjects/python-otr/blob/master/setup.py#L22

[Mic92]

backport:
[detached HEAD e15c928] python27Packages.application: 2.7.0 -> 2.8.0 and fix build
Author: Benjamin Hipple [email protected]
Date: Sun Mar 29 18:18:04 2020 -0400
1 file changed, 11 insertions(+), 6 deletions(-)
Press Enter to continue
[detached HEAD 81c29c1] python27Packages.python-otr: mark as broken
Author: Benjamin Hipple [email protected]
Date: Sun Mar 29 18:42:39 2020 -0400
1 file changed, 5 insertions(+), 2 deletions(-)