Qt Lottie doc build failing

Patch Set 3: Code-Review-1

Pre Continuous Integration Quick Check: Failed

Could not build documentation. The CI rejected the staged commits due to the beforementioned reason. Possible reason could be a bug in one of the commits or some more recent change. Please investigate it.

The error was in "qt/qt5", revision: 9f3386833f2f63f41941f3cbd73c9ad4c8a06ede

Build log: https://testresults.qt.io/logs/qt/qt5/723fa179491f538f6ad1d8da4d4ba0677b1c3c04/LinuxUbuntu_18_04x86_64LinuxUbuntu_18_04x86_64GCCqtci-linux-Ubuntu-18.04-x86_64-9a8851DeveloperBuild_OutOfSourceBuild_QtLibInfix_QtNamespace_BuildExamples_Documentation/2a48a3b7dcb9652b1532a3ad14de7580b5b9b1ee/build_1550072455/log.txt.gz

Details: https://testresults.qt.io/coin/integration/qt/qt5/tasks/web_qt_qt5_1548306513245

Change: https://codereview.qt-project.org/#/c/250118/

From log:

agent:2019/01/24 06:10:46 build.go:192: make[4]: Entering directory '/home/qt/work/build/qtlottie/src/imports'
agent:2019/01/24 06:10:46 build.go:192: /home/qt/work/build/qtlottie/src/imports/qhelpgenerator_wrapper.sh /home/qt/work/build/qtbase/doc/lottieanimation/lottieanimation.qhp -o /home/qt/work/build/qtbase/doc/lottieanimation.qch
agent:2019/01/24 06:10:46 build.go:192: cd hello_speak/ && ( test -e Makefile || /home/qt/work/build/qtbase/bin/qmake -o Makefile /home/qt/work/qt/qt5/qtspeech/examples/speech/hello_speak/hello_speak.pro ) && make -f Makefile qch_docs
agent:2019/01/24 06:10:46 build.go:192: Could not open /home/qt/work/build/qtbase/doc/lottieanimation/lottieanimation.qhp.
agent:2019/01/24 06:10:46 build.go:192: Makefile:602: recipe for target 'qch_docs' failed
agent:2019/01/24 06:10:46 build.go:192: make[4]: *** [qch_docs] Error 255
agent:2019/01/24 06:10:46 build.go:192: make[4]: Leaving directory '/home/qt/work/build/qtlottie/src/imports'
agent:2019/01/24 06:10:46 build.go:192: Makefile:606: recipe for target 'sub-imports-qch_docs_ordered' failed
agent:2019/01/24 06:10:46 build.go:192: make[3]: *** [sub-imports-qch_docs_ordered] Error 2
agent:2019/01/24 06:10:46 build.go:192: make[3]: Leaving directory '/home/qt/work/build/qtlottie/src'
agent:2019/01/24 06:10:46 build.go:192: Makefile:552: recipe for target 'sub-src-qch_docs' failed
agent:2019/01/24 06:10:46 build.go:192: make[2]: *** [sub-src-qch_docs] Error 2
agent:2019/01/24 06:10:46 build.go:192: make[2]: Leaving directory '/home/qt/work/build/qtlottie'
agent:2019/01/24 06:10:46 build.go:192: Makefile:2084: recipe for target 'module-qtlottie-qch_docs' failed
agent:2019/01/24 06:10:46 build.go:192: make[1]: *** [module-qtlottie-qch_docs] Error 2
agent:2019/01/24 06:10:46 build.go:192: make[1]: *** Waiting for unfinished jobs....