Use literal_eval instead of safe_eval whenever possible

CVE-2014-6633
issue4155
review10521002
(grafted from 33dc5c84a9025a78899cf0eac24516ff87bb10a9)

--HG--
branch : 2.4
extra : source : 33dc5c84a9025a78899cf0eac24516ff87bb10a9
Prevent double underscore in safe_eval

CVE-2014-6633
issue4155
review5601002
(grafted from 3db7377f9429ac4419721e86fc46c8e2b2f341f2)

--HG--
branch : 2.4
extra : source : 3db7377f9429ac4419721e86fc46c8e2b2f341f2
Prepare release 2.4.15

--HG--
branch : 2.4
Added tag 2.4.15 for changeset 57b61cd6f113

--HG--
branch : 2.4
Increase version number

--HG--
branch : 2.4