Use a string literal format to avoid a gcc warning (-Wformat-security)


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@14047 a5019735-40e9-0310-863c-91ae7b9d1cf9
Refine NEWS entry for helgrind Ada tasks intercepts


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@14048 a5019735-40e9-0310-863c-91ae7b9d1cf9