Skip all ruby distrib tests that use ruby 2.2

tools/run_tests/artifacts/distribtest_targets.py

@@ -336,17 +336,18 @@ def targets():
         PythonDistribTest('linux', 'x64', 'ubuntu1404', source=True),
         PythonDistribTest('linux', 'x64', 'ubuntu1604', source=True),
         RubyDistribTest('linux', 'x64', 'wheezy'),
-        RubyDistribTest('linux', 'x64', 'jessie', ruby_version='ruby_2_2'),
         RubyDistribTest('linux', 'x64', 'jessie', ruby_version='ruby_2_3'),
         RubyDistribTest('linux', 'x64', 'jessie', ruby_version='ruby_2_4'),
         RubyDistribTest('linux', 'x64', 'jessie', ruby_version='ruby_2_5'),
         RubyDistribTest('linux', 'x64', 'jessie', ruby_version='ruby_2_6'),
-        RubyDistribTest('linux', 'x64', 'centos6'),
+        # TODO(apolcyn): unskip these after upgrading the ruby versions
-        RubyDistribTest('linux', 'x64', 'centos7'),
+        # of these dockerfiles to >= 2.3.
-        RubyDistribTest('linux', 'x64', 'fedora20'),
+        #   RubyDistribTest('linux', 'x64', 'centos6'),
-        RubyDistribTest('linux', 'x64', 'fedora21'),
+        #   RubyDistribTest('linux', 'x64', 'centos7'),
-        RubyDistribTest('linux', 'x64', 'fedora22'),
+        #   RubyDistribTest('linux', 'x64', 'fedora20'),
-        RubyDistribTest('linux', 'x64', 'fedora23'),
+        #   RubyDistribTest('linux', 'x64', 'fedora21'),
+        #   RubyDistribTest('linux', 'x64', 'fedora22'),
+        #   RubyDistribTest('linux', 'x64', 'fedora23'),
         RubyDistribTest('linux', 'x64', 'opensuse'),
         RubyDistribTest('linux', 'x64', 'ubuntu1204'),
         RubyDistribTest('linux', 'x64', 'ubuntu1404'),