roll gyp 2028:2029

r2029: mac: Followup to ZERO_AR_DATE, touch the -o archive, rather than expecting only one

TBR=thakis@chromium.org
BUG=342974,451499

Review URL: https://codereview.chromium.org/887753002

Cr-Commit-Position: refs/heads/master@{#313757}

DEPS

@@ -161,7 +161,7 @@ deps = {
     Var('chromium_git') + '/external/grit-i18n.git' + '@' + 'a5890a8118c0c80cc0560e6d8d5cf65e5d725509', # from svn revision 185
 
   'src/tools/gyp':
-    Var('chromium_git') + '/external/gyp.git' + '@' + 'b28bd7ddd1438c98f93a8e5383b7daceb572a3fb', # from svn revision 2028
+    Var('chromium_git') + '/external/gyp.git' + '@' + '104e21ecf6f28c47d2e729d572aa790b85225ee0', # from svn revision 2029
 
   'src/tools/swarming_client':
    Var('chromium_git') + '/external/swarming.client.git' + '@' +  Var('swarming_revision'),