oeqa/targetcontrol: Rework exception handling to avoid warnings

We're seeing:

WARNING: bitbake/lib/bb/cookerdata.py:136: ResourceWarning: unclosed file <_io.FileIO
name='tmp/work/qemux86_64-poky-linux/core-image-minimal/1.0-r0/testimage/qemurunner_log.20200601181912'
mode='ab' closefd=True

which can only be caused by the qemu.stop() method not being called.
Tweak the error handling to fix the blanket exception handler which
is likely meaning this function isn't getting called.

(From OE-Core rev: bd2d32903f208b6a70abaa29b980db1498b84a02)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit ee707090848d793e3b2d82dd3861ae22222682c0)
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oeqa/targetcontrol.py

@@ -182,7 +182,10 @@ class QemuTarget(BaseTarget):
         return self.runner.is_alive()
 
     def stop(self):
-        self.runner.stop()
+        try:
+            self.runner.stop()
+        except:
+            pass
         self.logger.removeHandler(self.loggerhandler)
         self.connection = None
         self.ip = None

meta/lib/oeqa/utils/commands.py

@@ -351,10 +351,7 @@ def runqemu(pn, ssh=True, runqemuparams='', image_fstype=None, launch_cmd=None,
 
     finally:
         targetlogger.removeHandler(handler)
-        try:
-            qemu.stop()
-        except:
-            pass
+        qemu.stop()
 
 def updateEnv(env_file):
     """