bot_update: fix git dir check

recipe_modules/bot_update/resources/bot_update.py

Index: recipe_modules/bot_update/resources/bot_update.py
diff --git a/recipe_modules/bot_update/resources/bot_update.py b/recipe_modules/bot_update/resources/bot_update.py
index ac4254dd292d9f1cf6ddef94e77e2812195021ba..15c29fa2f26456d2a7324e10239c97e391a278e2 100755
--- a/recipe_modules/bot_update/resources/bot_update.py
+++ b/recipe_modules/bot_update/resources/bot_update.py
@@ -828,7 +828,7 @@ def need_to_run_deps2git(repo_base, deps_file, deps_git_file):
                        last_known_deps_git_ref, cwd=repo_base).strip()
 
   # If the merge base of the last DEPS and last .DEPS.git file is not
-  # equivilent to the hash of the last DEPS file, that means the DEPS file
+  # equivalent to the hash of the last DEPS file, that means the DEPS file
   # was committed after the last .DEPS.git file.
   return last_known_deps_ref != merge_base_ref
 
@@ -960,7 +960,7 @@ def git_checkout(solutions, revisions, shallow, refs, git_cache_dir):
           'clone', '--no-checkout', '--local', '--shared', mirror_dir, sln_dir)
 
       try:
-        if not path.isdir(sln_dir):
+        if not path.isdir(os.path.join(sln_dir, '.git')):
           git(*clone_cmd)
         else:
           git('remote', 'set-url', 'origin', mirror_dir, cwd=sln_dir)