Fix git on non-Windows. Fix create_sdk on machines using svn.

utils/pub/io.dart

Index: utils/pub/io.dart
diff --git a/utils/pub/io.dart b/utils/pub/io.dart
index e39a9ccbe08c9fce5fc9d1310e3c390526db13ea..19117f541d6f98d7e5d23417999e89e2d91ef8c1 100644
--- a/utils/pub/io.dart
+++ b/utils/pub/io.dart
@@ -543,9 +543,9 @@ Future<bool> get isGitInstalled {
     // TODO(rnystrom): The sleep is to pump the message queue. Can use
     // Future.immediate() when #3356 is fixed.
     return sleep(0).transform((_) => _isGitInstalledCache);
-
-    return _gitCommand.transform((git) => git != null);
   }
+
+  return _gitCommand.transform((git) => git != null);
 }
 
 /// Run a git process with [args] from [workingDir].