Bugzilla 750: hoist "xml" namespace

This turns out to be caused by a issue in one of the libraries underlying xmlsectool.  Work around this for now by passing the output from xmlsectool through Xalan again using an identity transform.  This strips the problematic declarations without affecting the signature.

build.xml

@@ -574,6 +574,10 @@
 		<attribute name="i"/><!-- input file, assumed to be in the XML directory -->
 		<attribute name="o"/><!-- output file, assumed to be in the XML directory -->
 		<sequential>
+			<!-- delete the temporary file to be sure we don't use old data -->
+			<delete file="${xml.dir}/temp.xml" quiet="true" verbose="false"/>
+
+			<!-- perform signing operation into temporary file -->
 			<XMLSECTOOL i="@{i}">
 				<args>
 					<arg value="--sign"/>
@@ -586,14 +590,28 @@
 					<arg value="--keyPassword"/>
 					<arg value="${keystore.pass}"/>
 					<arg value="--outFile"/>
-					<arg value="${xml.dir}/@{o}"/>
+					<arg value="${xml.dir}/temp.xml"/>
 					<arg value="--referenceIdAttributeName"/>
 					<arg value="ID"/>
 					<!--
 					<arg value="- -quiet"/>
 					-->
 				</args>
 			</XMLSECTOOL>
+
+			<!--
+				Perform identity transform, into the real output file.
+				
+				This will remove some problematic "xml" namespace prefix
+				declarations without affecting the signature.
+			-->
+			<XALAN
+				i="temp.xml"
+				o="@{o}"
+				x="identity.xsl"/>
+
+			<!-- delete the temporary file now that we're finished with it -->
+			<delete file="${xml.dir}/temp.xml" quiet="true" verbose="false"/>
 		</sequential>
 	</macrodef>