qga: rename Error ** parameter to more common errp

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20191205174635.18758-13-vsementsov@virtuozzo.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
diff --git a/qga/commands-win32.c b/qga/commands-win32.c
index 55ba5b2..2461fd1 100644
--- a/qga/commands-win32.c
+++ b/qga/commands-win32.c
@@ -1946,7 +1946,7 @@
 
 } GA_WTSINFOA;
 
-GuestUserList *qmp_guest_get_users(Error **err)
+GuestUserList *qmp_guest_get_users(Error **errp)
 {
 #define QGA_NANOSECONDS 10000000