This update for ebook-tools fixes the following issues:
* Fix a crash when a navPoint in toc.ncx has no navLabel, see kde#406116 and https://sourceforge.net/p/ebook-tools/bugs/8/
+ add 0001-Avoid-crash-on-toc-navPoint-without-navLabel.patch
* specfile cleanup, remove %defattr, add LICENSE

This update was imported from the openSUSE:Leap:15.1:Update update project.