Merge PR coq#7471: [travis] Fix version of camlp5 for OCaml 4.06.1.

.travis.yml

@@ -41,7 +41,7 @@ env:
   - COMPILER="system"
   - COMPILER_BE="4.06.1"
   - CAMLP5_VER=".6.14"
-  - CAMLP5_VER_BE=".7.03"
+  - CAMLP5_VER_BE=".7.05"
   - FINDLIB_VER=".1.4.1"
   - FINDLIB_VER_BE=".1.8.0"
   - LABLGTK="lablgtk.2.18.3 lablgtk-extras.1.6"
@@ -278,6 +278,7 @@ install:
 - if [ "${TRAVIS_OS_NAME}" == "linux" ]; then travis_retry ./dev/tools/sudo-apt-get-update.sh -q; fi
 - if [ "${TRAVIS_OS_NAME}" == "linux" ]; then sudo apt-get install -y opam aspcud gcc-multilib; fi
 - opam init -j ${NJOBS} --compiler=${COMPILER} -n -y
+- opam switch "$COMPILER" && opam update
 - eval $(opam config env)
 - opam config list
 - opam install -j ${NJOBS} -y num camlp5${CAMLP5_VER} ocamlfind${FINDLIB_VER} ${EXTRA_OPAM}