fix unnecessary irep_free
Merge pull request #1202 from masahino/fix_load.c

fix unnecessary irep_free on load.c
Fix segfault on loading binary RITE files.
Set ENV before loading Rakefile in minirake
Fix wrong comment
Merge pull request #1208 from tomykaira/fix_wrong_symbol_comment

Fix wrong comment
Merge pull request #1204 from monaka/pr-fix-segfault-on-loading-binary-mrb

Fix segfault on loading binary RITE files.
Merge pull request #1207 from h2so5/set-env-before-loading-rakefile

Set ENV before loading Rakefile in minirake