Add explicit dependency to org.eclipse.gef

Change-Id: I7c0f9dab83fdd6468ae96aa9b8c3780feaac695e
Signed-off-by: Stéphane Thibaudeau <stephane.thibaudeau@obeo.fr>
diff --git a/plugins/org.eclipse.emf.compare.diagram.ide.ui.sirius/META-INF/MANIFEST.MF b/plugins/org.eclipse.emf.compare.diagram.ide.ui.sirius/META-INF/MANIFEST.MF
index 9798be7..a4cdf24 100644
--- a/plugins/org.eclipse.emf.compare.diagram.ide.ui.sirius/META-INF/MANIFEST.MF
+++ b/plugins/org.eclipse.emf.compare.diagram.ide.ui.sirius/META-INF/MANIFEST.MF
@@ -19,7 +19,8 @@
  org.eclipse.emf.compare.diagram,
  org.eclipse.emf.compare.diagram.ide.ui;bundle-version="3.0.0",
  org.eclipse.sirius.diagram;bundle-version="3.0.0",
- org.eclipse.gmf.runtime.notation;bundle-version="1.8.0"
+ org.eclipse.gmf.runtime.notation;bundle-version="1.8.0",
+ org.eclipse.gef
 Import-Package: com.google.common.annotations;version="[15.0.0,22.0.0)",
  com.google.common.base;version="[15.0.0,22.0.0)",
  com.google.common.cache;version="[15.0.0,22.0.0)",