buildhistory: show time spent writting buildhistory

* especially when pushing longer history to slow remote git server or when
  it timeouts during the push, it's useful to see where the time was actually
  spent

(From OE-Core rev: 96f1225d47985d94d9ed91eb5e7affdd70671c79)

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/buildhistory.bbclass

@@ -839,11 +839,15 @@ python buildhistory_eventhandler() {
             if e.data.getVar("BUILDHISTORY_COMMIT") == "1":
                 bb.note("Writing buildhistory")
                 bb.build.exec_func("buildhistory_write_sigs", d)
+                import time
+                start=time.time()
                 localdata = bb.data.createCopy(e.data)
                 localdata.setVar('BUILDHISTORY_BUILD_FAILURES', str(e._failures))
                 interrupted = getattr(e, '_interrupted', 0)
                 localdata.setVar('BUILDHISTORY_BUILD_INTERRUPTED', str(interrupted))
                 bb.build.exec_func("buildhistory_commit", localdata)
+                stop=time.time()
+                bb.note("Writing buildhistory took: %s seconds" % round(stop-start))
             else:
                 bb.note("No commit since BUILDHISTORY_COMMIT != '1'")
 }