Make building from bleeding edge tarball possible without Subversion installed

tools/utils.py

Index: tools/utils.py
diff --git a/tools/utils.py b/tools/utils.py
index 49ff0b112c5a0f1e7b70c997e99006507e74dba2..a8ad21d307fbff86d5acc8971f3ade9c49d612f2 100644
--- a/tools/utils.py
+++ b/tools/utils.py
@@ -318,6 +318,14 @@ def ReadVersionFile():
     return None
 
 def GetSVNRevision():
+  # When building from tarball use tools/SVN_REVISION
+  svn_revision_file = os.path.join(DART_DIR, 'tools', 'SVN_REVISION')
+  try:
+    with open(svn_revision_file) as fd:
+      return fd.read()
+  except:
+    pass
+
   # FIXME(kustermann): Make this work for newer SVN versions as well (where
   # we've got only one '.svn' directory)
   custom_env = dict(os.environ)
@@ -339,14 +347,6 @@ def GetSVNRevision():
   if revision:
     return revision
 
-  # When building from tarball use tools/SVN_REVISION
-  svn_revision_file = os.path.join(DART_DIR, 'tools', 'SVN_REVISION')
-  try:
-    with open(svn_revision_file) as fd:
-      return fd.read()
-  except:
-    pass
-
   # Only fail on the buildbot in case of a SVN client version mismatch.
   user = GetUserName()
   if user != 'chrome-bot':