WebDAV: Handle propagation of remote color/name change to local color/name update consistently
As communicated at https://bugzilla.gnome.org/show_bug.cgi?id=795869, Evolution is supposed to synchronize the CalDAV calendar colors locally, anytime they are changed on the server, unless these were not changed locally.
When evolution-source-registry crashes the account data (can get in theory and somehow this happens in practice) is lost. When for whatever reason collection accounts are set up, Evolution might not get the colors from the server. In both cases Evolution has some colors for the local calendars, and these cannot be synchronized with the remove calendars.
https://bugzilla.gnome.org/show_bug.cgi?id=795870#c10 says that after set up, colors on the server and local colors are separate things.
This separation shall be consistent with regards to the WebDAV displayname/url and the local calendar/addressbook name.
As outlined at #223 (comment 852925), when on the remote site the display name changes (or rather: when on the remote site the URL was used to name a local collection and later the remote resource gets DAV:displayname), Evolution fetches the displayname and updates the local names of calendars and addressbooks.
To summarize: • When the remote name is changed, local names are updated • When the remote color is changed, local colours are not updated
This seems to be unrelated to whether locally the color was changed or not.