Need to normalize the output of QFileInfo::canonicalFilePath() before
comparing to a server side path.
See https://bugreports.qt-project.org/browse/QTBUG-39622

This fixes #1998 and #1999

Otherwise the SHibbolethCredential may be set and it has hook to intercept 401

This should fix issue #1908

When using the "Limit automatically" limit, we wait for 25% of the time
it took to upload something.
However, if we go to sleep while uploading, the time it took to upload may take
days. And waiting for 25% of a day is too long.
So never wait for more than 10 seconds

This may be related to issue #1880

Issue #1982

If the local folder changes, the sync has to be reinitialized as
well. Until now we did not detect that, which led to the case that
the sync folder was not reinitialized in case only the local folder
changed in the setup dialog.

Before, we would only detect it if all the files were removed, and no
file where added or changed. This may not be enough because there might
be a welcome.txt file. Now, we check that none of the file stays the same,
and some files are removed.

Relates issue #1948

Fix the signature so it can be connected

This was hapenning if the derver does not support X-OC-MTime

issue #1963

Fixes #1957

That should save memory instead of letting the number of items grow
to infinity

The idea here was that the buffer would be maximum 8KiB, not minimum.

Fix #1915

But in case the user clicks cancel in the interactive dialog, invalidate
the credentials. Emit fechted() also in error case.

Earlier clients used QtKeychain without a QSettings object, which made
QtKeychain to write the password encrypted into a settings default
location, ie. the registry under windows.

If we can not find a password at the new location it is tried to read
the password from the old default location once. That makes people
happy in migration scenarios.

Otherwise the user is asked twice for autentication on first sync.

Fixes https://github.com/owncloud/enterprise/issues/193

If we don't have the cookie in the keychain (e.g. the keychain is
unavailable) but there is still session cookie in the cookie jar,
showing the browser won't ask for authentication.

This fixes Coverity CLT 12893

This break the test.
And the function is aleady gone in master anyway

This reverts commit 407b3beb.

This fixes Coverity CID 12912

This fixes Coverity CID 12914

This fixes Coverity CID 12915

This fixes coverity CID 12916

This fixes coverity CID 12919

This fixes Coverity CID 12922

This fixes coverity issue 12925

This fixes Coverity CID 12926

This fixes Coverity CID 12927