cherry pick 46cd2f4 for CVE-2013-4164

merge revision(s) 43775:

	* util.c (ruby_strtod): ignore too long fraction part, which does not
	  affect the result.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@43778 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

Conflicts:
	ChangeLog
	test/ruby/test_float.rb
	version.h