Depend on at-spi2-core to pre-install it.

BUG: 141626176
Change-Id: Id3308f2afdf310116adc3d91ad7d8dd505ba485c
diff --git a/debian/control b/debian/control
index a116a92..025192f 100644
--- a/debian/control
+++ b/debian/control
@@ -7,7 +7,8 @@
 
 Package: mendel-core
 Priority: optional
-Depends: mdt-services,
+Depends: at-spi2-core,
+         mdt-services,
          mendel-distro-info-data,
          mendel-keyring,
          mendel-minimal,