Fix GetPrimarySolutionPath() to not include buildtools

GetPrimarySolutionPath() is used by GetBuildtoolsPath() to locate
the chromium/src directory, its return value shouldn't include
'buildtools', since GetBuildtoolsPath() will append another one to
it.

Introduced by https://codereview.chromium.org/933383002

Review URL: https://codereview.chromium.org/1072973003

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@294894 0039d316-1c4b-4281-b951-d872f2087c98

gclient_utils.py

@@ -679,7 +679,7 @@ def GetPrimarySolutionPath():
       pass
     top_dir = top_dir[0]
     if os.path.exists(os.path.join(top_dir, 'buildtools')):
-      return os.path.join(top_dir, 'buildtools')
+      return top_dir
     return None
 
   # Some projects' top directory is not named 'src'.