set "UserCmdCheckStatus" to "1" by default

This change requires all post/pre commands to be set, as "undef" will actually
fail the backup run. Setting this to "true" by default will make the commands
always run the "0" exit status, successfully running the backup runs.
set "ssh_password" attribute to "nil" by default

passing "false" to `OpenSSL::PKey::RSA#new` as it's second argument failed the
run. Passing "nil" should make the method ignore the password argument.
bundle update

also: Disable new "SingleSpaceBeforeFirstArg" cop
Release v1.2.0