* numeric.c (do_coerce): fix for the exceptions which the coerce
  method raises.  The optimization done by r38756 is preserved.
  [Bug #7645] [ruby-core:51213]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@38792 b2dd03c8-39d4-4d8f-98ff-823fe69b080e