Don't remove the VS2015 runtime libraries in a clobber build.
Don't remove the VS2015 runtime libraries in a clobber build.

These files are copied to the output directory by the vs_toolchain script:
https://code.google.com/p/chromium/codesearch#chromium/src/build/vs_toolchain.py&l=104

Review URL: https://codereview.chromium.org/1565493002

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@298130 0039d316-1c4b-4281-b951-d872f2087c98

eunchong/build,eunchong/build,eunchong/build,eunchong/build