As hicolor-icon-theme owns the directories under /usr/share/icons/hicolor, and gtk2 depends on hicolor-icon-theme, it is sufficient to own only the files under that directory.
Created attachment 966018 [details] proposed patch
claws-mail-3.11.1-3.fc20 has been submitted as an update for Fedora 20. https://admin.fedoraproject.org/updates/claws-mail-3.11.1-3.fc20
claws-mail-3.11.1-3.fc21 has been submitted as an update for Fedora 21. https://admin.fedoraproject.org/updates/claws-mail-3.11.1-3.fc21
Package claws-mail-3.11.1-3.fc20: * should fix your issue, * was pushed to the Fedora 20 testing repository, * should be available at your local mirror within two days. Update it with: # su -c 'yum update --enablerepo=updates-testing claws-mail-3.11.1-3.fc20' as soon as you are able to. Please go to the following url: https://admin.fedoraproject.org/updates/FEDORA-2015-0957/claws-mail-3.11.1-3.fc20 then log in and leave karma (feedback).
claws-mail-3.11.1-3.fc21 has been pushed to the Fedora 21 stable repository. If problems still persist, please make note of it in this bug report.
claws-mail-3.11.1-3.fc20 has been pushed to the Fedora 20 stable repository. If problems still persist, please make note of it in this bug report.