QMimeDatabase re-adds/prepends the "main" glob pattern (the first one
in the system-wide xml file) to the glob patterns list, even if the user
has previously removed it e.g. via the filetypes kcm, as a result of that:

• Don't change the sort order of m_patterns. It seems the list returned by QMimeType::globPatterns() is "ordered". Also no need to sort() the patterns list in the unit test or in MimeTypeData::isMimeTypeDirty()
• Disable the "Remove" button for the first entry in the glob patterns list view

Fix filetypetest (unit test), use "*.inf" instead of "*.txt", the latter
was always re-added by QMimeDatabase, which made the test fail.

Before applying the diff:

• • Open the filetypes kcm, and remove the first glob pattern, "*.mp3" from audio/mpeg, apply, restart, note that it's been added back to the top of the list.
• Go to text/plain mimetype, the first entry isn't "*.txt"

• Apply the diff then try again, the "Remove" button should be disabled when you select the first row in the patterns list view.
• Select a different entry, "Remove" button should become enabled.
• Go to text/plain mimetype, "*.txt" is the first entry.