Fix SQLite Synapse runs

Broke in #1390

lib/SyTest/Homeserver.pm

@@ -374,11 +374,9 @@ sub _get_dbconfigs
    foreach my $db ( keys %db_configs ) {
       my $db_config = $db_configs{$db};
 
-      # Extract the name of the module that is used to access the database. This
-      # does add a new item to the database config block, 'type'. It appears to
-      # be harmless and is used later on to determine which method to use to
-      # clear the database
-      my $db_name = $db_config->{name};
+      # Backwards compatibility: the `type` field in the sytest database config
+      # used to be called `name` and have different values. We fix that up here.
+      my $db_name = delete $db_config->{name};
       if( defined $db_name ) {
          if( $db_name eq 'psycopg2' ) {
             $db_config->{type} = 'pg';

lib/SyTest/Homeserver/Synapse.pm

@@ -125,6 +125,21 @@ sub start
       },
    );
 
+   # convert sytest db args onto synapse db args
+   for my $db ( keys %db_configs ) {
+      my %db_config = %{ $db_configs{$db} };
+
+      my $db_type = $db_config{type};
+
+      if( $db_type eq "pg" ) {
+         $db_configs{$db}{name} = 'psycopg2';
+      }
+      else {
+         # must be sqlite
+         $db_configs{$db}{name} = 'sqlite3';
+      }
+   }
+
    # Clean up the media_store directory each time, or else it fills up with
    # thousands of automatically-generated avatar images
    if( -d "$hs_dir/media_store" ) {