cannot install fts-rest via pip on EL7

(fts-tests) [root@fts-dev-andrea examples]# pip install fts3-rest-API
Collecting fts3-rest-API
Downloading https://files.pythonhosted.org/packages/e1/4e/bc06cf96a9871b1b465ec0438a1cd32395b8709490b7fd0b4c063b018f1a/fts3-rest-API-3.7.1.tar.gz
Requirement already satisfied: M2Crypto>=0.16 in /tmp/fts-tests/lib/python2.7/site-packages (from fts3-rest-API)
Collecting pycurl>=7.19 (from fts3-rest-API)
Using cached https://files.pythonhosted.org/packages/e8/e4/0dbb8735407189f00b33d84122b9be52c790c7c3b25286826f4e1bdb7bde/pycurl-7.43.0.2.tar.gz
Complete output from command python setup.py egg_info:
Using curl-config (libcurl 7.29.0)
Traceback (most recent call last):
File "<string>", line 1, in <module>
File "/tmp/pip-build-DsWgh5/pycurl/setup.py", line 913, in <module>
ext = get_extension(sys.argv, split_extension_source=split_extension_source)
File "/tmp/pip-build-DsWgh5/pycurl/setup.py", line 582, in get_extension
ext_config = ExtensionConfiguration(argv)
File "/tmp/pip-build-DsWgh5/pycurl/setup.py", line 99, in _init_
self.configure()
File "/tmp/pip-build-DsWgh5/pycurl/setup.py", line 316, in configure_unix
specify the SSL backend manually.''')
_main_.ConfigurationError: Curl is configured to use SSL, but we have not been able to determine which SSL backend it is using. Please see PycURL documentation for how to specify the SSL backend manually.

----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-DsWgh5/pycurl/