[gnome-software] Use a constant to represent an unknown install date

[Richard Hughes <rhughes src gnome org>]

commit e11f98cd038c971eef39e83a946f80cca9751ed8
Author: Richard Hughes <richard hughsie com>
Date:   Thu Sep 12 11:41:53 2013 +0100

    Use a constant to represent an unknown install date

 src/gs-app.h                               |    2 ++
 src/plugins/gs-plugin-packagekit-history.c |    4 ++--
 2 files changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/src/gs-app.h b/src/gs-app.h
index ac03b91..0b6d918 100644
--- a/src/gs-app.h
+++ b/src/gs-app.h
@@ -73,6 +73,8 @@ typedef enum {
        GS_APP_STATE_LAST
 } GsAppState;
 
+#define        GS_APP_INSTALL_DATE_UNKNOWN             1 /* 1s past the epoch */
+
 GQuark          gs_app_error_quark             (void);
 GType           gs_app_get_type                (void);
 
diff --git a/src/plugins/gs-plugin-packagekit-history.c b/src/plugins/gs-plugin-packagekit-history.c
index 32a5718..6c31a5e 100644
--- a/src/plugins/gs-plugin-packagekit-history.c
+++ b/src/plugins/gs-plugin-packagekit-history.c
@@ -178,7 +178,7 @@ gs_plugin_packagekit_refine (GsPlugin *plugin,
                         * trying to call GetPackageHistory */
                        for (l = list; l != NULL; l = l->next) {
                                app = GS_APP (l->data);
-                               gs_app_set_install_date (app, 1);
+                               gs_app_set_install_date (app, GS_APP_INSTALL_DATE_UNKNOWN);
                        }
                } else {
                        ret = FALSE;
@@ -198,7 +198,7 @@ gs_plugin_packagekit_refine (GsPlugin *plugin,
                if (!ret) {
                        g_debug ("no history for %s, setting timestamp nonzero",
                                 gs_app_get_source (app));
-                       gs_app_set_install_date (app, 1);
+                       gs_app_set_install_date (app, GS_APP_INSTALL_DATE_UNKNOWN);
                        continue;
                }