coverity#1411565 'Constant' variable guards dead code

on incomplete fix of

commit 922e935c
Date:   Mon May 29 17:08:06 2017 +0200

    i18nutil: fix invalid string copy that prevents startup

for

commit ef513fd4
Date:   Fri May 26 10:58:42 2017 +0200

    remove unnecessary use of OString::getStr

Change-Id: I6cc56bae5e4a5c2fb235663bc6676cdea02b9701

i18nutil/source/utility/paper.cxx

@@ -271,7 +271,8 @@ PaperInfo PaperInfo::getSystemDefaultPaper()
 
                 if (ePaper == PAPER_USER)
                 {
-                    if (aPaper.startsWith("half"))
+                    bHalve = aPaper.startsWith("half");
+                    if (bHalve)
                     {
                         aPaper = aPaper.copy(4);
                     }