[zorg] Remove unused BOTO_CONFIG settings from arm and aarch64 builders.

[maxim-kuvyrkov]

This is a trivial cleanup that was split up from an approved patch: https://reviews.llvm.org/D42039

buildbot/osuosl/master/config/builders.py

return [
          'slavenames':["linaro-tk1-04"],
          'builddir':"clang-cmake-armv7-a15-selfhost-neon",
          'factory' : ClangBuilder.getClangCMakeBuildFactory(
                       clean=False,
                       checkout_compiler_rt=False,
                       checkout_lld=False,
                       useTwoStage=True,
                       testStage1=False,
-                      env={'BOTO_CONFIG':'/var/buildbot/llvmlab-build-artifacts.boto'},
                       extra_cmake_args=["-DCMAKE_C_COMPILER_LAUNCHER='ccache'",
                                         "-DCMAKE_CXX_COMPILER_LAUNCHER='ccache'",
                                         "-DCMAKE_C_FLAGS='-mcpu=cortex-a15 -marm'",
                                         "-DCMAKE_CXX_FLAGS='-mcpu=cortex-a15 -marm'",
                                         "-DLLVM_TARGETS_TO_BUILD='ARM;AArch64'",
                                         "-DLLVM_LIT_ARGS='-sv -j2'",
                                         "-DLLVM_PARALLEL_LINK_JOBS=2"])},
 
return [
                       clean=False,
                       checkout_compiler_rt=False,
                       checkout_lld=False,
                       test=True,
                       useTwoStage=False,
                       runTestSuite=True,
                       testsuite_flags=['--cppflags', '-mcpu=cortex-a57',
                                        '--threads=8', '--build-threads=8'],
-                      env={'BOTO_CONFIG':'/var/buildbot/llvmlab-build-artifacts.boto'},
                       extra_cmake_args=["-DCMAKE_C_COMPILER_LAUNCHER='ccache'",
                                         "-DCMAKE_CXX_COMPILER_LAUNCHER='ccache'",
                                         "-DCMAKE_C_FLAGS='-mcpu=cortex-a57'",
                                         "-DCMAKE_CXX_FLAGS='-mcpu=cortex-a57'",
                                         "-DLLVM_TARGETS_TO_BUILD='ARM;AArch64'"],
                )},
 
         ## AArch64 Self-hosting Clang+LLVM check-all + LLD + test-suite