Correct typo

Author: Eric Rasche

tools/xpath/xpath.xml

@@ -6,7 +6,7 @@
   </macros>
   <!--<expand macro="requirements"/>-->
   <expand macro="stdio"/>
-  <command intepreter="bash"><![CDATA[xpath
+  <command interpreter="bash"><![CDATA[xpath
       -q
       -e '$expression' $input > $output
       ]]></command>