Make api.env.nss_dir relative to api.env.confdir

api.env.nss_dir is no longer hard-coded to paths.IPA_NSSDB_DIR. Instead
the path is calculated relatively to api.env.confdir. The default value
is still /etc/ipa/nssdb. The change makes it a bit easier to run
FreeIPA's API with a custom configuration directory.

See https://fedorahosted.org/freeipa/ticket/6386

Signed-off-by: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Tomas Krizek <tkrizek@redhat.com>
Reviewed-By: Jan Cholasta <jcholast@redhat.com>

ipalib/config.py

@@ -474,6 +474,9 @@ class Env(object):
         if 'conf_default' not in self:
             self.conf_default = self._join('confdir', 'default.conf')
 
+        if 'nss_dir' not in self:
+            self.nss_dir = self._join('confdir', 'nssdb')
+
         # Set plugins_on_demand:
         if 'plugins_on_demand' not in self:
             self.plugins_on_demand = (self.context == 'cli')