oeqa/buildperf: Add 'bitbake -m' on sync function to ensure bitbake is unloaded

Add 'bitbake -m' to the sync method and ensure all process related to
bitbake are correctly unloaded before doing the different measurements.
Also add a call to sync funtion on Test4 before final measurment of
eSDK deploy dir disk usage.

(From OE-Core rev: 9210c9ce051dfffaa7afa36bb4a926cea289ffd4)

Signed-off-by: Jose Perez Carranza <jose.perez.carranza@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oeqa/buildperf/base.py

@@ -485,6 +485,7 @@ class BuildPerfTestCase(unittest.TestCase):
     @staticmethod
     def sync():
         """Sync and drop kernel caches"""
+        runCmd2('bitbake -m', ignore_status=True)
         log.debug("Syncing and dropping kernel caches""")
         KernelDropCaches.drop()
         os.sync()

meta/lib/oeqa/buildperf/test_basic.py

@@ -121,5 +121,7 @@ class Test4(BuildPerfTestCase):
         self.sync()
         self.measure_cmd_resources([installer, '-y', '-d', deploy_dir],
                                    'deploy', 'eSDK deploy')
+        #make sure bitbake is unloaded
+        self.sync()
         self.measure_disk_usage(deploy_dir, 'deploy_dir', 'deploy dir',
                                 apparent_size=True)