depot_tools: Add git svn find-rev for safesync_url parsing (commonly LKGR link).

tests/gclient_scm_test.py

Index: tests/gclient_scm_test.py
===================================================================
--- tests/gclient_scm_test.py	(revision 109214)
+++ tests/gclient_scm_test.py	(working copy)
@@ -85,10 +85,21 @@
 
   def testDir(self):
     members = [
-        'FullUrlForRelativeUrl', 'GetRevisionDate', 'RunCommand',
-        'cleanup', 'diff', 'pack', 'relpath', 'revert',
-        'revinfo', 'runhooks', 'status', 'update',
-        'updatesingle', 'url',
+        'FullUrlForRelativeUrl',
+        'GetRevisionDate',
+        'GetUsableRev',
+        'RunCommand',
+        'cleanup',
+        'diff',
+        'pack',
+        'relpath',
+        'revert',
+        'revinfo',
+        'runhooks',
+        'status',
+        'update',
+        'updatesingle',
+        'url'
     ]
 
     # If you add a member, be sure to add the relevant test!
@@ -619,10 +630,21 @@
 
 class ManagedGitWrapperTestCase(BaseGitWrapperTestCase):
   def testDir(self):
-    members = [
-        'FullUrlForRelativeUrl', 'GetRevisionDate', 'RunCommand',
-        'cleanup', 'diff', 'pack', 'relpath', 'revert',
-        'revinfo', 'runhooks', 'status', 'update', 'url',
+    members = [ 
+        'FullUrlForRelativeUrl',
+        'GetRevisionDate',
+        'GetUsableRev',
+        'RunCommand',
+        'cleanup',
+        'diff',
+        'pack',
+        'relpath',
+        'revert',
+        'revinfo',
+        'runhooks',
+        'status',
+        'update',
+        'url'
     ]
 
     # If you add a member, be sure to add the relevant test!