svx: extend SvxNumType with BITMAP and CHARS_UPPER_LETTER_N

With abaf6bde (tdf#65642 RTF filter: import
\pgnrestart and \pgnucltr, 2016-03-22), CppunitTest_sw_rtfimport causes an
SvxPageItem::eNumType (of type enum SvxNumType, with values 0--7) to contain a
value 9 (which suspiciously is css.style.NumberingType.CHARS_UPPER_LETTER_N),
which is undefined behavior.

Extend the internal enum (which is supposed to be a prefix ot the UNO API one)
to contain two more items. Should fix the problem pointed out at
<http://ci.libreoffice.org/job/lo_ubsan/212/console>.

Change-Id: I91b8c38de357ceee9e8691e15f885cdfbc0ef7ca

include/svx/pageitem.hxx

@@ -32,7 +32,9 @@ enum SvxNumType
     SVX_ARABIC,
     SVX_NUMBER_NONE,
     SVX_CHAR_SPECIAL,
-    SVX_PAGEDESC
+    SVX_PAGEDESC,
+    SVX_BITMAP,
+    SVX_CHARS_UPPER_LETTER_N
 };
 
 /*--------------------------------------------------------------------