Merge pull request #5586 from stanley-cheung/update-tools-readme-md

Doc Fixit: remove old stuff from tools/README.md

tools/README.md

 buildgen: template renderer for our build system.
 
-distpackages: script to generate debian packages.
-
 distrib: scripts to distribute language-specific packages.
 
 dockerfile: Docker files to test gRPC.
@@ -12,6 +10,4 @@ gce: scripts to help setup testing infrastructure on GCE.
 
 jenkins: support for running tests on Jenkins.
 
-profile_analyzer: pretty printer for gRPC profiling data.
-
 run_tests: scripts to run gRPC tests in parallel.