Remove remaining debug symbols

[Smjert]

I recently noticed that an osquery Release build contains debug information.

I've tested with a simple cpp file and indeed our clang creates a Release binary with some debug symbols.
Checking the toolchain provided files I noticed that /usr/local/osquery-toolchain/lib/libc-2.12.2.so for instance is marked having debug symbols.
I'm not sure why, since I've built clang with MinSizeRel and crosstool-ng should be also building in Release mode.
Anyway, I think we need to double check the configuration.