Fix uninitialized constant error

Signed-off-by: Vasu1105 <vasundhara.jagdale@msystechnologies.com>

lib/train/platforms/detect/helpers/os_common.rb

@@ -34,7 +34,7 @@ def command_output(cmd)
       # When you try to execute command using ssh connction as root user and you have provided ssh user identity file
       # it gives standard output to login as authorised user other than root. To show this standard ouput as an error
       # to user we are matching the string of stdout and raising the error here so that user gets exact information.
-      if @backend.class == Train::Transports::SSH::Connection && res =~ /Please login as the user/
+      if @backend.class.to_s == "Train::Transports::SSH::Connection" && res =~ /Please login as the user/
         raise Train::UserError, "SSHFailed: #{res}"
       end
       res.strip! unless res.nil?