Don't perform an XInclude to a document node that may not always be present

Because some of the manager events are defined in the top of the source, due
to the macro calls not containing all necessary information to have the
documentation colocated with the call itself, several include statements were
failing when built with 'make'.  While this did not cause any problems in
compilation or validation, it did result in a number of warnings being dumped
to stderr.

This patch changes those references such that they always resolve, regardless
of the documentation build options.

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@369939 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/features.c

@@ -475,9 +475,13 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 		<managerEventInstance class="EVENT_FLAG_CALL">
 			<synopsis>Raised when a parked call times out.</synopsis>
 			<syntax>
-				<xi:include xpointer="xpointer(/docs/managerEvent[@name='ParkedCall']/managerEventInstance/syntax/parameter[@name='Exten'])" />
+				<parameter name="Exten">
+					<para>The parking lot extension.</para>
+				</parameter>
 				<parameter name="Channel"/>
-				<xi:include xpointer="xpointer(/docs/managerEvent[@name='ParkedCall']/managerEventInstance/syntax/parameter[@name='Parkinglot'])" />
+				<parameter name="Parkinglot">
+					<para>The name of the parking lot.</para>
+				</parameter>
 				<parameter name="CallerIDNum"/>
 				<parameter name="CallerIDName"/>
 				<parameter name="ConnectedLineNum"/>
@@ -493,9 +497,9 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 		<managerEventInstance class="EVENT_FLAG_CALL">
 			<synopsis>Raised when a parked call hangs up while in the parking lot.</synopsis>
 			<syntax>
-				<xi:include xpointer="xpointer(/docs/managerEvent[@name='ParkedCall']/managerEventInstance/syntax/parameter[@name='Exten'])" />
+				<xi:include xpointer="xpointer(/docs/managerEvent[@name='ParkedCallTimeOut']/managerEventInstance/syntax/parameter[@name='Exten'])" />
 				<parameter name="Channel"/>
-				<xi:include xpointer="xpointer(/docs/managerEvent[@name='ParkedCall']/managerEventInstance/syntax/parameter[@name='Parkinglot'])" />
+				<xi:include xpointer="xpointer(/docs/managerEvent[@name='ParkedCallTimeOut']/managerEventInstance/syntax/parameter[@name='Parkinglot'])" />
 				<parameter name="CallerIDNum"/>
 				<parameter name="CallerIDName"/>
 				<parameter name="ConnectedLineNum"/>