bitbake: cooker: Log when parsing starts in server log

It is unclear from the server logs when parsing starts. We know that timeouts
sometimes happen when parsing but it is unclear where in the code the delays
are from. Adding this debug message to the server log should help narrow
that down.

(Bitbake rev: a5c145f436d68f090b113cfb9b82857adc95b546)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/cooker.py

@@ -1666,6 +1666,7 @@ class BBCooker:
             self.updateCacheSync()
 
         if self.state != state.parsing and not self.parsecache_valid:
+            bb.server.process.serverlog("Parsing started")
             self.setupParserWatcher()
 
             bb.parse.siggen.reset(self.data)