Fix lockfile versions

[peterhurford]

• run("titanic") works.
• run("survey") works.
• run("uci") works.

[peterhurford]

F--- travis

[peterhurford]

@robertzk I keep getting Can not use tracked environments with stagerunners that have caching disabled (remember = FALSE) on run("survey") and I can't figure out why.

[peterhurford]

@robertzk @kirillseva Also run("uci") dies on Error: there is no package called ‘gbm’. I think this is a problem we've had before and solved before?

[robertzk]

@peterhurford If you call run with multiple cores, separate threads are spun up which are not in the lockbox session. We install gbm globally and typically do not encounter the problem but I haven't figured out how to ensure the lockbox session persists to the gbm threads.

[robertzk]

@peterhurford By default objectdiff is currently enabled, so try setting options("environment_type" = "environment") globally. I'm not sure why the stagerunner is getting created with remember = FALSE given the initialization but I can take a look this weekend.

[peterhurford]

Fixed in #16 but should retry to ensure all the examples run