Fix stack trace from %W prompt format

Should have been framework.db.active.

Author: wvu

lib/rex/ui/text/shell.rb

@@ -178,7 +178,7 @@ def run(&block)
           input.prompt.gsub!(/%J/, framework.jobs.length.to_s)
           input.prompt.gsub!(/%L/, Rex::Socket.source_address("50.50.50.50"))
           input.prompt.gsub!(/%D/, ::Dir.getwd)
-          if framework.db && framework.db.workspace
+          if framework.db.active
             input.prompt.gsub!(/%W/, framework.db.workspace.name)
           end
           self.init_prompt = input.prompt