Fix git-try, was broken by r58936.

git-try

Index: git-try
diff --git a/git-try b/git-try
index 9eaec61bac10819f4c36e6b9c5ff6d5ea8950bf5..e61831a5df2e7346d226d11cd6e81fe451e6d1fd 100755
--- a/git-try
+++ b/git-try
@@ -9,25 +9,32 @@ import sys
 
 import breakpad
 
+import gclient_utils
 from scm import GIT
 import trychange
 
 
 def GetRietveldIssueNumber():
-  return GIT.Capture(
-      ['config', 'branch.%s.rietveldissue' % GIT.GetBranch(None)],
-      error_ok=True)[0]
+  try:
+    return GIT.Capture(
+        ['config', 'branch.%s.rietveldissue' % GIT.GetBranch(None)])
+  except gclient_utils.Error:
+    return None
 
 
 def GetRietveldPatchsetNumber():
-  return GIT.Capture(
-      ['config', 'branch.%s.rietveldpatchset' % GIT.GetBranch(None)],
-      error_ok=True)[0]
+  try:
+    return GIT.Capture(
+        ['config', 'branch.%s.rietveldpatchset' % GIT.GetBranch(None)])
+  except gclient_utils.Error:
+    return None
 
 
 def GetRietveldServerUrl():
-  return GIT.Capture(
-      ['config', 'rietveld.server'], error_ok=True)[0].strip()
+  try:
+    return GIT.Capture(['config', 'rietveld.server']).strip()
+  except gclient_utils.Error:
+    return None
 
 
 if __name__ == '__main__':