Drop bogus memset

..that is both bad and unnecessary since
8003f8694a "loplugin:useuniqueptr in
oneToOneMappingWithFlag" changed oneToOneMappingWithFlag::mpIndex from an array
of raw pointers to an array of std::unique_ptr.

Change-Id: I247a619ebd7804a8a4faee2797f8c4753f9c4ec6
Reviewed-on: https://gerrit.libreoffice.org/80288
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

i18nutil/source/utility/oneToOneMapping.cxx

@@ -18,7 +18,6 @@
  */
 
 #include <i18nutil/oneToOneMapping.hxx>
-#include <string.h>
 
 namespace i18nutil {
 
@@ -63,7 +62,6 @@ oneToOneMappingWithFlag::oneToOneMappingWithFlag( UnicodePairWithFlag const *rpT
       mnFlag    ( rnFlag ),
       mbHasIndex( false )
 {
-    memset(mpIndex, 0, sizeof(mpIndex));
 }
 
 oneToOneMappingWithFlag::~oneToOneMappingWithFlag()