Don't interpreter blank string as error

Author: OJ

lib/rex/post/meterpreter/ui/console/command_dispatcher/powershell.rb

@@ -105,10 +105,12 @@ def cmd_powershell_import(*args)
     }
 
     result = client.powershell.import_file(opts)
-    if !result.blank? && result != false
-      print_good("File successfully imported. Result:\n#{result}")
-    else
+    if result.nil? || result == false
       print_error("File failed to load.")
+    elsif result.empty?
+      print_good("File successfully imported. No result was returned.")
+    else
+      print_good("File successfully imported. Result:\n#{result}")
     end
   end