make scriptcondition behave as documented wrt script return value

src/main/org/apache/tools/ant/types/optional/ScriptCondition.java

@@ -44,8 +44,8 @@ public class ScriptCondition extends AbstractScriptComponent implements Conditio
     @Override
     public boolean eval() throws BuildException {
         initScriptRunner();
-        executeScript("ant_condition");
-        return getValue();
+        final Object result = getRunner().evaluateScript("ant_condition");
+        return Boolean.TRUE.equals(result) || getValue();
     }
 
     /**

src/tests/antunit/types/optional/scriptcondition-test.xml

@@ -68,4 +68,20 @@
     </au:assertFalse>
   </target>
 
+  <target name="test-return-value-true">
+    <au:assertTrue>
+      <scriptcondition language="beanshell">
+        true
+      </scriptcondition>
+    </au:assertTrue>
+  </target>
+
+  <target name="test-return-value-false">
+    <au:assertTrue>
+      <scriptcondition language="beanshell" value="true">
+        false
+      </scriptcondition>
+    </au:assertTrue>
+  </target>
+
 </project>