Ban any dependency on 'futures'

'futures' provides concurrent.futures, which has been part of the Python
standard library since the 3.2 release, so it should not be added as a
dependency anymore.

Any remaining Python 2 packages can manually require
'deprecated-futures-legacypython' as needed.

Signed-off-by: Patrick McCarty <patrick.mccarty@intel.com>

autospec/buildreq.py

@@ -29,7 +29,7 @@ import config
 import toml
 import util
 
-banned_requires = set()
+banned_requires = set(["futures"])
 buildreqs = set()
 buildreqs_cache = set()
 requires = set()
@@ -43,7 +43,8 @@ banned_buildreqs = set(["llvm-devel",
                         "tslib-0.0",
                         "pkgconfig(parallels-sdk)",
                         "oslo-python",
-                        "libxml2No-python"])
+                        "libxml2No-python",
+                        "futures"])
 autoreconf_reqs = ["gettext-bin",
                    "automake-dev",
                    "automake",