oeqa: Add exception handling around qemu process cleanup

The qemu processes may no longer exist at the end of the test so
don't error if that is the case by ignoring any exceptions.

(From OE-Core rev: 64c531282e756965365c742751846250a2c1d3f1)

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

meta/lib/oeqa/selftest/imagefeatures.py

@@ -68,7 +68,10 @@ class ImageFeatures(oeSelfTest):
             proc_ssh.terminate()
 
         # Cleanup
-        killpg(proc_qemu.pid, signal.SIGTERM)
+        try:
+            killpg(proc_qemu.pid, signal.SIGTERM)
+        except:
+            pass
 
     @testcase(1115)
     def test_all_users_can_connect_via_ssh_without_password(self):
@@ -121,7 +124,10 @@ class ImageFeatures(oeSelfTest):
             proc_ssh.terminate()
 
         # Cleanup
-        killpg(proc_qemu.pid, signal.SIGTERM)
+        try:
+            killpg(proc_qemu.pid, signal.SIGTERM)
+        except:
+            pass
 
     @testcase(1114)
     def test_rpm_version_4_support_on_image(self):
@@ -167,7 +173,10 @@ class ImageFeatures(oeSelfTest):
                       'RPM version is not {}, found instead {}.'.format(rpm_version, found_rpm_version))
 
         # Cleanup (close qemu)
-        killpg(proc_qemu.pid, signal.SIGTERM)
+        try:
+            killpg(proc_qemu.pid, signal.SIGTERM)
+        except:
+            pass
 
     @testcase(1116)
     def test_clutter_image_can_be_built(self):