[silicon] enable only silicon tests in travis.

.travis.yml

@@ -16,7 +16,7 @@ env:
     #
     #
     #- "TESTDIR=C/libreactor"
-    - "TESTDIR=C/lwan"
+    #- "TESTDIR=C/lwan"
     #- "TESTDIR=C/duda"
     #- "TESTDIR=C/haywire"
     #- "TESTDIR=C/onion"
@@ -26,7 +26,7 @@ env:
     ## - "TESTDIR=CSharp/HttpListener"
     #- "TESTDIR=CSharp/nancy"
     #- "TESTDIR=CSharp/servicestack"
-    - "TESTDIR=C++/cpoll_cppsp"
+    #- "TESTDIR=C++/cpoll_cppsp"
     - "TESTDIR=C++/silicon"
     #- "TESTDIR=C++/treefrog"
     #- "TESTDIR=C++/ulib"