hotfix for runtime reflection

Recent runtime reflection sync pull request, which among other things,
introduced more restricted package completion rules, led to a nightmarish
regression on java7, which prevented the entire scalac from starting up.

This commit temporarily disables the introduced assert in order to hotfix
runtime reflection. In the hours to come I'll be looking into the root of
the problem, preparing a pull request that reinstates the assert, which
indicates a bug in our code that's been there since 2.10.0-M3, and fixes
the said bug.

Details: https://groups.google.com/forum/#!topic/scala-internals/hcnUFk75MgQ