Move the valgrind mac bots to be on 10.5 instead of 10.6 to get rid of the memory errors we are currently seeing.
Move the valgrind mac bots to be on 10.5 instead of 10.6
to get rid of the memory errors we are currently seeing.

Review URL: http://codereview.chromium.org/3901003

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@63113 0039d316-1c4b-4281-b951-d872f2087c98

eunchong/build,eunchong/build,eunchong/build,eunchong/build