[R-Source] Fix Assignment.getSourceExpr for right versions

The error had no impact, because the method is currently not used.

Change-Id: I609d425c4e44e0cc6658326029b42c946134f5c8
diff --git a/r/org.eclipse.statet.r.core/src/org/eclipse/statet/r/core/rsource/ast/Assignment.java b/r/org.eclipse.statet.r.core/src/org/eclipse/statet/r/core/rsource/ast/Assignment.java
index 1f3e5ce..a13aaf1 100644
--- a/r/org.eclipse.statet.r.core/src/org/eclipse/statet/r/core/rsource/ast/Assignment.java
+++ b/r/org.eclipse.statet.r.core/src/org/eclipse/statet/r/core/rsource/ast/Assignment.java
@@ -241,7 +241,7 @@
 		
 		@Override
 		final Expression getSourceExpr() {
-			return this.rightExpr;
+			return this.leftExpr;
 		}
 		
 		@Override
@@ -286,7 +286,7 @@
 		
 		@Override
 		final Expression getSourceExpr() {
-			return this.rightExpr;
+			return this.leftExpr;
 		}
 		
 		@Override