process: Fix »no step/action/host specified« cases.
llvm: llvm llvmf85ec865f0f803273ab38e3b1a19fe185c7e88ac (2012-12-23), clang debc018be39668db5cefb6418cd210aa716d6e7a (2012-12-23), compiler-rt cab6133c5d7478e96882cb54467e29b3716c0d89 (2012-12-23), test-suite 1451ba86fc87d067ed3d244352e4025a8134b0a7 (2012-12-23)
For diff, use log_[step].diff.sed files instead of log_[step].sed.
llvm/*/log_build.sed: New.
llvm/*/log_test.sed: Filter away » (n of N)«.