2013-07-30: Fix giving empty nicknames to GetIdentitiesByPartialNickname.

Fix giving empty nicknames to GetIdentitiesByPartialNickname. Doing so results in an exception in LCWoT's query layer, for which it does not return an error over FCP, (I think?) so Infocalypse's FCP times out.

diff --git a/infocalypse/wot_id.py b/infocalypse/wot_id.py
--- a/infocalypse/wot_id.py
+++ b/infocalypse/wot_id.py
@@ -131,39 +131,38 @@ def _get_identity(wot_identifier, truste
     # TODO: Should this manually ensure an identity has a vcs context
     # otherwise?
 
-    # LCWoT can have * to allow a wildcard match, but a wildcard alone is
-    # not allowed. See Lucine Term Modifiers documentation. The nickname
-    # uses this syntax but the ID is inherently startswith().
-    params = {'Message': 'GetIdentitiesByPartialNickname',
-              'Truster': truster.identity_id,
-              'PartialNickname':
-              nickname_prefix + '*' if nickname_prefix else '',
-              'PartialID': key_prefix,
-              'MaxIdentities': 2,
-              'Context': 'vcs'}
+    # GetIdentitiesByPartialNickname does not support empty nicknames.
+    if nickname_prefix:
+        params = {'Message': 'GetIdentitiesByPartialNickname',
+                  'Truster': truster.identity_id,
+                  'PartialNickname':
+                  nickname_prefix + '*',
+                  'PartialID': key_prefix,
+                  'MaxIdentities': 2,
+                  'Context': 'vcs'}
 
-    response = \
-        node.fcpPluginMessage(async=False,
-                              plugin_name="plugins.WebOfTrust.WebOfTrust",
-                              plugin_params=params)[0]
+        response = \
+            node.fcpPluginMessage(async=False,
+                                  plugin_name="plugins.WebOfTrust.WebOfTrust",
+                                  plugin_params=params)[0]
 
-    if response['header'] != 'FCPPluginReply' or \
-            'Replies.Message' not in response:
-        raise util.Abort('Unexpected reply. Got {0}\n'.format(response))
-    elif response['Replies.Message'] == 'Identities':
-        matches = response['Replies.IdentitiesMatched']
-        if matches == 0:
-            raise util.Abort("No identities match '{0}'\n".format(
-                wot_identifier))
-        elif matches == 1:
-            return response
-        else:
-            raise util.Abort("'{0}' is ambiguous.\n".format(wot_identifier))
+        if response['header'] != 'FCPPluginReply' or \
+                'Replies.Message' not in response:
+            raise util.Abort('Unexpected reply. Got {0}\n'.format(response))
+        elif response['Replies.Message'] == 'Identities':
+            matches = response['Replies.IdentitiesMatched']
+            if matches == 0:
+                raise util.Abort("No identities match '{0}'\n".format(
+                    wot_identifier))
+            elif matches == 1:
+                return response
+            else:
+                raise util.Abort("'{0}' is ambiguous.\n".format(wot_identifier))
 
-    # Partial matching not supported, or unknown truster. The only
-    # difference in the errors is human-readable, so just try the exact
-    # match.
-    assert response['Replies.Message'] == 'Error'
+        # Partial matching not supported, or unknown truster. The only
+        # difference in the errors is human-readable, so just try the exact
+        # match.
+        assert response['Replies.Message'] == 'Error'
 
     # key_prefix must be a complete key for the lookup to succeed.
     params = {'Message': 'GetIdentity',