Improve boolean parsing in Expressions

Instead of Boolean.valueOf(value).booleanValue() use
Boolean.parseBoolean(value);

Done via the Primitive parsing cleanup from JDT UI

Change-Id: I692ac96817309da2485e14ea69bf58b75d2a45f7
Signed-off-by: Lars Vogel <Lars.Vogel@vogella.com>
diff --git a/bundles/org.eclipse.core.expressions/src/org/eclipse/core/internal/expressions/Expressions.java b/bundles/org.eclipse.core.expressions/src/org/eclipse/core/internal/expressions/Expressions.java
index 83e0d5a..0bc774b 100644
--- a/bundles/org.eclipse.core.expressions/src/org/eclipse/core/internal/expressions/Expressions.java
+++ b/bundles/org.eclipse.core.expressions/src/org/eclipse/core/internal/expressions/Expressions.java
@@ -263,14 +263,14 @@
 		String value= element.getAttribute(attributeName);
 		if (value == null)
 			return false;
-		return Boolean.valueOf(value).booleanValue();
+		return Boolean.parseBoolean(value);
 	}
 
 	public static boolean getOptionalBooleanAttribute(Element element, String attributeName) {
 		String value= element.getAttribute(attributeName);
 		if (value.isEmpty())
 			return false;
-		return Boolean.valueOf(value).booleanValue();
+		return Boolean.parseBoolean(value);
 	}
 
 	//---- Argument parsing --------------------------------------------