(maint) Fix package tests

[rodjek]

• PDK now lays down a Gemfile.lock when initialising a module, so we can't expect it to be absent.
• Remove the DEPENDENCIES section of the Gemfile.lock before comparing. This section only lists the specified depedencies whereas the GEMS section is more important as it contains all the fully resolved dependencies. The DEPENDENCIES section can cause false failures in cases where different ways of specifying the dependency resolve to the same version e.g. puppet (~> 6.0) != puppet (= 6.0.4) even though they resolve to the same version.
• Either the SUITE_VERSION env var changed for OSX or the path vanagon creates changed since the last release. In any case, the path to the .pkg in the .dmg has changed and we need to update our OSX package install logic.

[coveralls]

Coverage remained the same at 92.994% when pulling 547e816 on rodjek:fix-package-tests into d4d1c9d on puppetlabs:master.

[rodjek]

https://jenkins-master-prod-1.delivery.puppetlabs.net/view/PDK/job/platform_pdk_pdk-int-sys-testing_master/370/