Remove modified flag when merging downloaded data

[stoecker]

When new server data is downloaded and the merging process shows an object is flagged as modified, but identical to to server data, then modified should be removed.

Notes:

• Ensure Undo/Redo set modify again
• Be sure data is really unmodified
• Offer to download all modified primitives before upload?

This should reduce the number of useless changed elements a lot (at least when download before upload is done).

[mjulius]

(In [2624]) fixes #4088,#4155 - when after conflict resolving the primitive has equal semantic attributes as theirs, the primitive will get the same modified flag as theirs.

[stoecker]

Sorry, but you did not fix this issue.

You can test it like that:

• add a new node to a way
• delete that node again --> you get a useless modified state
• redownload area --> still useless modified state

[mjulius]

(In [2634]) really fixes #4088 - Remove modified flag when merging downloaded data

[Don-vip]

In 15444/josm:

fix #18212, see #4088, see #4155 - don't override modified flag of deleted primitives after resolving a conflict