Code review comment for lp:~widelands-dev/widelands/campaign_data

I get an error too, from ASAN. There is some illegal data passed to Profile by that line.

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==10374==ERROR: AddressSanitizer: stack-use-after-scope on address 0x7ffe6d2c9300 at pc 0x7f9ba515b66e bp 0x7ffe6d2c8d80 sp 0x7ffe6d2c8528
READ of size 3 at 0x7ffe6d2c9300 thread T0
    #0 0x7f9ba515b66d (/usr/lib/x86_64-linux-gnu/libasan.so.4+0x5166d)
    #1 0x55b57ce0c51d in boost::range_detail::length(char const*) /usr/include/boost/range/as_literal.hpp:38
    #2 0x55b57ce2093e in boost::iterator_range<char const*> boost::range_detail::make_range<char const>(char const*, bool) /usr/include/boost/range/as_literal.hpp:86
    #3 0x55b57cee0d81 in boost::iterator_range<boost::range_iterator<char const* const, void>::type> boost::as_literal<char const*>(char const* const&) /usr/include/boost/range/as_literal.hpp:109
    #4 0x55b57dd78425 in bool boost::algorithm::equals<char const*, char const*, boost::algorithm::is_iequal>(char const* const&, char const* const&, boost::algorithm::is_iequal) /usr/include/boost/algorithm/string/predicate.hpp:290
    #5 0x55b57dd77345 in bool boost::algorithm::iequals<char const*, char const*>(char const* const&, char const* const&, std::locale const&) /usr/include/boost/algorithm/string/predicate.hpp:346
    #6 0x55b57dd71a84 in Section::has_val(char const*) const src/profile/profile.cc:216
    #7 0x55b57db5209d in LuaBases::push_table_recursively(lua_State*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, Section*, Section*, Section*, Section*) src/scripting/lua_bases.cc:431
    #8 0x55b57db5330f in LuaBases::LuaEditorGameBase::read_campaign_data(lua_State*) src/scripting/lua_bases.cc:488