master.client.crashpad: fix x64 bot names
master.client.crashpad: fix x64 bot names

Followup to https://codereview.chromium.org/1354973003/ where
continuous.py had renamed the buildernames it expected, but builders.pyl
did not change them (win_rel -> win_x64_rel, etc.)

R=dpranke@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1357363002

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@296820 0039d316-1c4b-4281-b951-d872f2087c98

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