[llvm-cov] Don't use colored output until we know it's supported
[llvm-cov] Don't use colored output until we know it's supported

CodeCoverageTool::error() depends on CoverageViewOptions::Colors being
initialized. Should fix:

  http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fast/builds/56

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@285103 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 1fc13ff445141da145a48965b88dffc947ec56c6)

apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm