Revert "Save installed database in an atomic way"

This reverts commit 54bbe6bf.

src/zc/buildout/buildout.py

@@ -839,16 +839,11 @@ class Buildout(UserDict.DictMixin):
 
     def _update_installed(self, **buildout_options):
         installed = self['buildout']['installed']
-        # read old installed database
-        with open(installed, 'r') as f:
-            installed_data = f.read()
-
-        installed_data = '%s\n[buildout]\n' % installed_data
-        f = StringIO()
-        f.write(installed_data)
+        f = open(installed, 'a')
+        f.write('\n[buildout]\n')
         for option, value in buildout_options.items():
             _save_option(option, value, f)
-        self._save_installed_database(f.getvalue())
+        f.close()
 
     def _uninstall_part(self, part, installed_part_options):
         # uninstall part
@@ -1012,33 +1007,17 @@ class Buildout(UserDict.DictMixin):
                      for d in installed]
         return ' '.join(installed)
 
-    def _save_installed_database(self, text):
-        # Saved installed database in an atomic fashion
-        installed = self['buildout']['installed']
-        temp_installed = '%s.tmp' % installed
-        try:
-            with open(temp_installed, 'w') as f:
-                f.write(text)
-                f.flush()
-                os.fsync(f.fileno())
-            os.rename(temp_installed, installed)
-        finally:
-            try:
-                os.remove(temp_installed)
-            except OSError:
-                pass
 
     def _save_installed_options(self, installed_options):
         installed = self['buildout']['installed']
         if not installed:
             return
-        f = StringIO()
+        f = open(installed, 'w')
         _save_options('buildout', installed_options['buildout'], f)
         for part in installed_options['buildout']['parts'].split():
             print >>f
             _save_options(part, installed_options[part], f)
-
-        self._save_installed_database(f.getvalue())
+        f.close()
 
     def _error(self, message, *args):
         raise zc.buildout.UserError(message % args)