load.c: use RB_GC_GUARD
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51013 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
load.c: use RB_GC_GUARD
last use of feature.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51013 b2dd03c8-39d4-4d8f-98ff-823fe69b080e