Use the docstring as the description.

Both as the package description and the CLI description. Had to
workaround the botocore package missing in some cases (like pre-commit)
so the module can still be imported by setup.py.

eb_prune/__init__.py

@@ -7,7 +7,12 @@ from __future__ import (
     unicode_literals,
 )
 from argparse import ArgumentParser
+import sys
+
+try:
     from botocore import session  # pylint: disable=import-error
+except ImportError:
+    pass
 
 
 def prune(versions_to_keep, dry_run):
@@ -57,7 +62,7 @@ def prune(versions_to_keep, dry_run):
 
 
 def main():
-    parser = ArgumentParser()
+    parser = ArgumentParser(description=__doc__)
     parser.add_argument(
         "versions_to_keep", help="The number of versions to keep.", type=int
     )
@@ -72,4 +77,10 @@ def main():
 
 
 if __name__ == "__main__":
+    if "session" not in dir():
+        print(
+            "Failed to import botocore, is the package installed?",
+            file=sys.stderr,
+        )
+        sys.exit(2)
     main()

setup.py

 #!/usr/bin/env python
 from setuptools import setup, find_packages
+from eb_prune import __doc__ as description
 
 setup(
     name="eb-prune",
     version=open("VERSION", "r").read(),
-    description="Pruning of Elastic Beanstalk versions.",
+    description=description,
     long_description=open("README.rst", "r").read(),
     url="https://www.shore.co.il/git/eb-prune",
     author="Nimrod Adar",