yum: adds an auto_close attribute to the rpmdb object

This patch to PK should enable it to use the feature (if yum is patched.
If yum is not patched then this attribute set should do nothing at all)

backends/yum/yumBackend.py

@@ -2322,6 +2322,7 @@ class PackageKitYumBackend(PackageKitBaseBackend, PackagekitPackage):
 
         # set bandwidth throttle to 90%
         self.yumbase.conf.throttle = "90%"
+        self.yumbase.rpmdb.auto_close = True
         self.dnlCallback = DownloadCallback(self, showNames=True)
         self.yumbase.repos.setProgressBar(self.dnlCallback)