Fix coveralls error
```
coveralls --exclude src/libbson --exclude src/libmongoc --exclude src/contrib --exclude lib --exclude tests
Traceback (most recent call last):
File "/usr/local/bin/coveralls", line 6, in <module>
from pkg_resources import load_entry_point
File "/usr/local/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 3049, in <module>
@_call_aside
File "/usr/local/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 3033, in _call_aside
f(*args, **kwargs)
File "/usr/local/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 3062, in _initialize_master_working_set
working_set = WorkingSet._build_master()
File "/usr/local/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 658, in _build_master
ws.require(__requires__)
File "/usr/local/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 972, in require
needed = self.resolve(parse_requirements(requirements))
File "/usr/local/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 866, in resolve
new_requirements = dist.requires(req.extras)[::-1]
File "/usr/local/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 2590, in requires
"%s has no such extra feature %r" % (self, ext)
pkg_resources.UnknownExtra: urllib3 1.7.1 has no such extra feature 'secure'
make: *** [coveralls] Error 1
```
As already described at https://github.com/micropython/micropython/pull/3306#issuecomment-328342837, we should try to upgrade coveralls by specifying "--upgrade" to `pip install` and force pip to get the latest version of urllib3 as well.
This adds support for OpenSSL 1.1.x when building for PHP 7.1.2+.
Previously, we did not specify a custom path_to_check for crypt32.lib (see 912987c37d); however, SETUP_OPENSSL() does this for OpenSSL 1.0.x and lower, so we can add it back for consistency.
