[glom] UiUtils: Use font-family instead of font with GtkCssProvider.

[Murray Cumming <murrayc src gnome org>]

commit 0cf169bd5c26ac21d0f2dae1f4a01e3b3c155852
Author: Murray Cumming <murrayc murrayc com>
Date:   Mon May 16 19:19:04 2016 +0200

    UiUtils: Use font-family instead of font with GtkCssProvider.
    
    I think this is what this GtkCssProviderError runtime warning is
    asking for:
    Theme parsing error: <data>:1:19: Using Pango syntax for the font: style
    property is deprecated; please use CSS syntax

 glom/utils_ui.cc |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/glom/utils_ui.cc b/glom/utils_ui.cc
index 599fe86..4e008b9 100644
--- a/glom/utils_ui.cc
+++ b/glom/utils_ui.cc
@@ -603,7 +603,7 @@ void UiUtils::container_remove_all(Gtk::Container& container)
 
 void UiUtils::load_font_into_css_provider(Gtk::Widget& widget, const Glib::ustring& font)
 {
-  const auto css = "* { font: " + font + "; }";
+  const auto css = "* { font-family: " + font + "; }";
   load_into_css_provider(widget, css);
 }