Add package swiftclient (#15700)

* Add package swiftclient

* Fix on url

* Package name changed to py-python-swiftclient and changes on dependencies

var/spack/repos/builtin/packages/py-python-swiftclient/package.py

+# Copyright 2013-2019 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+from spack import *
+
+
+class PyPythonSwiftclient(PythonPackage):
+    """This is a python client for the Swift API."""
+
+    homepage = "https://docs.openstack.org/python-swiftclient"
+    url      = "https://pypi.io/packages/source/p/python-swiftclient/python-swiftclient-3.9.0.tar.gz"
+
+    maintainers = ['ajkotobi']
+
+    import_modules = ['sys', 'setuptools', 'requests']
+
+    version('3.9.0', sha256='4f2097492e4c76e948882fc859bfa033ade09bed72f8e6b328e34a3467d9a377')
+    version('3.8.1', sha256='3a013303643f77a99befa05582dfb93671e1fba1aed9f4a517418129700aedb8')
+    version('3.8.0', sha256='107a9d5356663365a9f7c0b3a2b55da97a0a9ba7f10da2319b3972481510f33d')
+    version('3.7.1', sha256='06bda5a6f81ea132e5cb52d0eb0616a0ab0958b4ec0d1cb7f850f04bf178852f')
+
+    depends_on('py-setuptools', type=('build', 'run'))
+    depends_on('python@2.7:', type=('build', 'run'))
+    depends_on('py-futures@3:', type=('build', 'run'), when='^python@:2')
+    depends_on('py-requests@1.1.0:', type=('build', 'run'))
+    depends_on('py-six@1.9:', type=('build', 'run'))
+    depends_on('py-pbr', type='build')