more formatting fixes

Found by flake8.

nominatim/db/async_connection.py

@@ -85,7 +85,7 @@ class DBConnection:
 
         # Use a dict to hand in the parameters because async is a reserved
         # word in Python3.
-        self.conn = psycopg2.connect(**{'dsn' : self.dsn, 'async' : True})
+        self.conn = psycopg2.connect(**{'dsn': self.dsn, 'async': True})
         self.wait()
 
         self.cursor = self.conn.cursor(cursor_factory=cursor_factory)

nominatim/db/sql_preprocessor.py

@@ -61,7 +61,7 @@ def _setup_postgresql_features(conn):
     """
     pg_version = conn.server_version_tuple()
     return {
-        'has_index_non_key_column' : pg_version >= (11, 0, 0)
+        'has_index_non_key_column': pg_version >= (11, 0, 0)
     }
 
 class SQLPreprocessor:

nominatim/db/utils.py

@@ -61,9 +61,9 @@ def execute_file(dsn, fname, ignore_errors=False, pre_code=None, post_code=None)
 
 
 # List of characters that need to be quoted for the copy command.
-_SQL_TRANSLATION = {ord(u'\\') : u'\\\\',
-                    ord(u'\t') : u'\\t',
-                    ord(u'\n') : u'\\n'}
+_SQL_TRANSLATION = {ord(u'\\'): u'\\\\',
+                    ord(u'\t'): u'\\t',
+                    ord(u'\n'): u'\\n'}
 
 class CopyBuffer:
     """ Data collector for the copy_from command.