Require configparser backport on 2.7

Save ourselves some branches and it's hard to test without because
pytest depends on it.

setup.py

@@ -46,7 +46,7 @@
     "Programming Language :: Python :: Implementation :: PyPy",
     "Topic :: Software Development :: Libraries :: Python Modules",
 ]
-INSTALL_REQUIRES = ["attrs>=17.4.0"]
+INSTALL_REQUIRES = ["attrs>=17.4.0", "configparser; python_version<'3.0'"]
 EXTRAS_REQUIRE = {"tests": ["pytest", "coverage"]}
 EXTRAS_REQUIRE["dev"] = EXTRAS_REQUIRE["tests"]
 

src/environ/secrets.py

@@ -18,18 +18,14 @@
 import logging
 import sys
 
+from configparser import NoOptionError, RawConfigParser
+
 import attr
 
 from ._environ_config import CNF_KEY, RAISE, _ConfigEntry
 from .exceptions import MissingSecretError
 
 
-try:
-    from configparser import RawConfigParser, NoOptionError
-except ImportError:
-    from ConfigParser import RawConfigParser, NoOptionError
-
-
 log = logging.getLogger(__name__)
 
 
@@ -168,9 +164,6 @@ def _load_ini(path):
     """
     cfg = RawConfigParser()
     with codecs.open(path, mode="r", encoding="utf-8") as f:
-        try:
-            cfg.read_file(f)
-        except AttributeError:
-            cfg.readfp(f)
+        cfg.read_file(f)
 
     return cfg