Silence warning C4701: potentially uninitialized local variable

Change-Id: Ia37347108f9fe7094f055a5c6f2ec9511c3aff1d

sal/textenc/tcvtutf8.cxx

@@ -68,7 +68,7 @@ sal_Size ImplConvertUtf8ToUnicode(
 {
     bool bJavaUtf8 = pData != nullptr;
     sal_uInt32 nUtf32 = 0;
-    int nBytes;
+    int nBytes = int();
     int nShift = -1;
     bool bCheckBom = true;
     sal_uInt32 nInfo = 0;