[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: https://llvm.org/svn/llvm-project/llvm/trunk@285103 91177308-0d34-0410-b5e6-96231b3b80d8

tools/llvm-cov/CodeCoverage.cpp

@@ -578,7 +578,7 @@ int CodeCoverageTool::run(Command Cmd, int argc, const char **argv) {
     for (const std::string &Filename : CovFilenames)
       ObjectFilenames.emplace_back(Filename);
     if (ObjectFilenames.empty()) {
-      error("No filenames specified!");
+      errs() << "No filenames specified!\n";
       ::exit(1);
     }
 
@@ -591,7 +591,7 @@ int CodeCoverageTool::run(Command Cmd, int argc, const char **argv) {
       break;
     case CoverageViewOptions::OutputFormat::HTML:
       if (UseColor == cl::BOU_FALSE)
-        error("Color output cannot be disabled when generating html.");
+        errs() << "Color output cannot be disabled when generating html.\n";
       ViewOpts.Colors = true;
       break;
     }