cleanup migrated XPointer module to the new error mechanism Daniel

* xpath.c: cleanup
* xpointer.c include/libxml/xmlerror.h: migrated XPointer module
  to the new error mechanism
Daniel
diff --git a/include/libxml/xmlerror.h b/include/libxml/xmlerror.h
index 546549c..f7ede83 100644
--- a/include/libxml/xmlerror.h
+++ b/include/libxml/xmlerror.h
@@ -537,7 +537,11 @@
     XML_SCHEMAV_ATTRUNKNOWN, /* 1819 */
     XML_SCHEMAV_ATTRINVALID, /* 1820 */
     XML_SCHEMAV_VALUE, /* 1821 */
-    XML_SCHEMAV_FACET /* 1822 */
+    XML_SCHEMAV_FACET, /* 1822 */
+    XML_XPTR_UNKNOWN_SCHEME = 1900,
+    XML_XPTR_CHILDSEQ_START, /* 1901 */
+    XML_XPTR_EVAL_FAILED, /* 1902 */
+    XML_XPTR_EXTRA_OBJECTS /* 1903 */
 } xmlParserErrors;
 
 /**