remove boost::thread in CI
diff --git a/.travis.yml b/.travis.yml
index 96e0b51..637b5d5 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -139,14 +139,6 @@
     # C++ specific options: compiler plug-in, threading model
     - script: build/docker/run.sh
       env:
-        - JOB="C++98 (Boost Thread)"
-        - SCRIPT="cmake.sh"
-        - BUILD_LIBS="CPP TESTING TUTORIALS"
-        - BUILD_ARG="-DCMAKE_CXX_STANDARD=98 -DCMAKE_CXX_STANDARD_REQUIRED=ON -DCMAKE_CXX_EXTENSIONS=OFF -DWITH_PYTHON=OFF -DWITH_C_GLIB=OFF -DWITH_JAVA=OFF -DWITH_HASKELL=OFF"
-        - BUILD_ENV="-e CC=clang -e CXX=clang++"
-
-    - script: build/docker/run.sh
-      env:
         - JOB="C++ (Std Thread) and Plugin"
         - SCRIPT="cmake.sh"
         - BUILD_LIBS="CPP TESTING TUTORIALS"