Fix crash when adding account in express mode

The settings library started using an EMailBackend object, but since
it is abstract it can't be instantiated directly. So we use the EShell
to get the mail backend for us instead, after loading the modules.

capplet/settings/Makefile.am

@@ -25,6 +25,7 @@ libevolution_mail_settings_la_CPPFLAGS =		\
 	-DEVOLUTION_PRIVDATADIR=\""$(privdatadir)"\"	\
 	-DEVOLUTION_ETSPECDIR=\""$(etspecdir)"\"	\
 	-DEVOLUTION_ICONSDIR=\""$(imagesdir)"\"		\
+	-DEVOLUTION_MODULEDIR=\""$(moduledir)"\"	\
 	-DEVOLUTION_IMAGES=\""$(imagesdir)"\"		\
 	-DEVOLUTION_GALVIEWSDIR=\""$(viewsdir)"\"	\
 	-DEVOLUTION_BUTTONSDIR=\""$(buttonsdir)"\"	\

capplet/settings/mail-capplet-shell.c

@@ -43,6 +43,8 @@
 #include <mail/mail-mt.h>
 #include <mail/e-mail-store.h>
 
+#include <shell/e-shell.h>
+
 enum {
 	CTRL_W_PRESSED,
 	CTRL_Q_PRESSED,
@@ -202,6 +204,7 @@ mail_capplet_shell_construct (MailCappletShell *shell, gint socket_id, gboolean
 {
 	MailCappletShellPrivate *priv = shell->priv;
 	GtkStyle *style = gtk_widget_get_default_style ();
+	EShell *eshell;
 	EMailSession *session;
 	gchar *custom_dir;
 
@@ -239,7 +242,30 @@ mail_capplet_shell_construct (MailCappletShell *shell, gint socket_id, gboolean
 
 	camel_provider_init ();
 
-	shell->priv->backend = g_object_new (E_TYPE_MAIL_BACKEND, NULL);
+	eshell = e_shell_get_default ();
+
+	if (eshell == NULL) {
+		GError *error = NULL;
+
+		eshell = g_initable_new (
+			E_TYPE_SHELL, NULL, &error,
+			"application-id", "org.gnome.Evolution",
+			"flags", 0,
+			"geometry", NULL,
+			"module-directory", EVOLUTION_MODULEDIR,
+			"meego-mode", FALSE,
+			"express-mode", FALSE,
+			"small-screen-mode", FALSE,
+			"online", FALSE,
+			NULL);
+
+		if (error != NULL)
+			g_error ("%s", error->message);
+
+		e_shell_load_modules (eshell);
+	}
+
+	shell->priv->backend = E_MAIL_BACKEND (e_shell_get_backend_by_name (eshell, "mail"));
 	session = e_mail_backend_get_session (shell->priv->backend);
 
 	shell->view = mail_view_new ();