#9191: fix enable/disable issues of buttons

At the http connection dialog, the 'Name' and 'Url' text boxes must be
filled to enable 'ok' button.
Also disable connect-edit-delete buttons when there is not any
connection defined.
#9191: More fixes
Merge pull request #1028 from ahuarte47/Issue_9191

Bug #9191-#9190: fix enable/disable issues of buttons