shill: Further deprecate CaCertNSS

Chrome has been updated to no longer set the CaCertNSS property
for OpenVPN, L2TP/IPSec and 802.1x connections.  It also has code
to migrate such properties over to the equivalent CaCertPEM
property.  This CL rips out the underpinnings in shill that used
to convert NSS properties by reading the user NSS database.  It
still supports the various NSS service properties for read (to
allow Chrome to detect and migrate away from the NSS property)
and write (so Chrome can clear the vestigial property) in all the
places where that was previously supported.

CQ-DEPEND=CL:205152
BUG=chromium:385401
TEST=Unit tests

Change-Id: Id3df385148acb8e9c4240bbaa980e4118aa6b088
Reviewed-on: https://chromium-review.googlesource.com/204763
Reviewed-by: Paul Stewart <pstew@chromium.org>
Commit-Queue: Paul Stewart <pstew@chromium.org>
Tested-by: Paul Stewart <pstew@chromium.org>
diff --git a/mock_eap_credentials.h b/mock_eap_credentials.h
index 36cd45e..5ba09bc 100644
--- a/mock_eap_credentials.h
+++ b/mock_eap_credentials.h
@@ -25,10 +25,8 @@
   MOCK_METHOD2(Load, void(StoreInterface *store, const std::string &id));
   MOCK_CONST_METHOD2(OutputConnectionMetrics,
                      void(Metrics *metrics, Technology::Identifier technology));
-  MOCK_CONST_METHOD4(PopulateSupplicantProperties, void(
+  MOCK_CONST_METHOD2(PopulateSupplicantProperties, void(
       CertificateFile *certificate_file,
-      NSS *nss,
-      const std::vector<char> nss_identifier,
       std::map<std::string, DBus::Variant> *params));
   MOCK_CONST_METHOD1(PopulateWiMaxProperties, void(KeyValueStore *params));
   MOCK_CONST_METHOD3(Save, void(