Travis: remove a redundant os: linux line

Linux is the first item in the os matrix, so we don't need to specify
it under matrix: include: .

Part of 29280.

diff --git a/.travis.yml b/.travis.yml
index 562036e51e5e065e32df0758b0b97f2aaa0115bc..190f43bd0128c30b623b4f9214293bc964fc9ec4 100644 (file)
--- a/.travis.yml
+++ b/.travis.yml
@@ -43,7 +43,6 @@ matrix:
     # We also try running a hardened clang build with chutney on Linux.
     - env: CHUTNEY="yes" SKIP_MAKE_CHECK="yes" CHUTNEY_ALLOW_FAILURES="2"
       compiler: clang
-      os: linux
 
   ## Uncomment to allow the build to report success (with non-required
   ## sub-builds continuing to run) if all required sub-builds have