History dialog changes its height depending on number of entries. It
is caused by the recent GtkScrolledWindow changes from Bug 766569. Set
fixed min and max content heights to avoid this behavioral.
https://bugzilla.gnome.org/show_bug.cgi?id=767065
The headerbar buttons with arrows were moved sidebyside by the commit
a70888f. The buttons have a slightly different size, which looks pretty
weird currently. Fix this by setting valign on GtkButton and not on
GtkImage inside.
https://bugzilla.gnome.org/show_bug.cgi?id=767065
Since we are setting the "Account Activity" title by prepending
the user real name ("%s - Account Activity") in um-history-dialog.c,
there's no need to set the title property for the dialog elsewhere.
https://bugzilla.gnome.org/show_bug.cgi?id=767065