[WIP] refactoring pkg/expect

[shjala]

Return error and let the user handle it the way they want, instead of exiting the program by calling log.Fatal().

Otherwise it makes causes some unexpected situations, for example PodDeploy returns an error but due to call to some functions from expect package, it might cause the program to log.Fatal() exit in the middle of the execution, robbing the caller of a decision on how to handle the error, for example change the app settings and try again.