Return to the build directory after installation.

.travis.yml

@@ -67,6 +67,7 @@ install:
           mkdir -p cmake && travis_retry wget --no-check-certificate --quiet -O - "${CMAKE_URL}" | tar --strip-components=1 -xz -C cmake
         fi
         export PATH="${DEPENDENCY_DIR}/cmake/bin:${PATH}"
+    - cd ${TRAVIS_BUILD_DIR}
 
 
 script: