fixed coverity_scan addon

Author: frsyuki

.travis.yml

@@ -45,13 +45,16 @@ env:
   global:
     - secure: "bWJR/alkUhovaZVn4EySamXsWsvAngLh/krZf3Jha6gYWGaf6HXFwB5gM9EaBIQsZKGECL9AKN0v8rX6tqSnXMKX2FgA9ClYvO0F60JviY6Ur6OT2rG0pm+WZZ1jzyGmf+5gVqiWF1/lM/tokdnj0Nw68OQwlNdc+DqxGXormO8="  # travis encrypt COVERITY_SCAN_TOKEN=...
 
+before_install:
+  - test "$TRAVIS_BRANCH" != "coverity_scan" -o ${TRAVIS_JOB_NUMBER##*.} = 1 || exit 0  # Skip build if branch is coverity_scan and this is the 1st job of the build matrix
+
 addons:
   coverity_scan:
     project:
       name: "msgpack/msgpack-ruby"
       description: "Build submitted via Travis CI"
     notification_email: frsyuki@gmail.com
     build_command_prepend: "bundle exec rake compile; cd tmp/x86_64-linux*/msgpack/*/; make clean"
-    build_command: "cd tmp/x86_64-linux*/msgpack/*/; make clean; make"
+    build_command: "bash -c 'cd tmp/x86_64-linux*/msgpack/*/; make clean; make'"
     branch_pattern: coverity_scan