Mac: Fix creation of dSYM files for the Release target by enabling the |mac_strip_release| GYP variable which was disabled in Chromium revision 235601.
Mac: Fix creation of dSYM files for the Release target by enabling the |mac_strip_release| GYP variable which was disabled in Chromium revision 235601.

git-svn-id: 66addb63d0c46e75f185859367c4faf62af16cdd@1541 5089003a-bbd8-11dd-ad1f-f1f9622dbc98

denzp/cef3,kuscsik/chromiumembedded,kuscsik/chromiumembedded,denzp/cef3,kuscsik/chromiumembedded,kuscsik/chromiumembedded,denzp/cef3,denzp/cef3