oeqa/parselogs: grep for exact errors list keywords

Given grep expression looks for error strings regardless of the semantics and this ends up it flagging things like

***********************
Log: /mnt/a/yoe/build/tmp/work/raspberrypi3_64-yoe-linux-musl/yoe-qt5-wayland-image/1.0-r0/target_logs/weston.log
-----------------------
Central error: EGL_KHR_create_context_no_error EGL_KHR_fence_sync
***********************

here EGL_KHR_create_context_no_error is an API, therefore the check should be tightened a bit so explicitly look for error words so such false positives don't show up

This helps in fixing wrong matches e.g. on rpi3 dmesg have strings like above

---
 meta/lib/oeqa/runtime/cases/parselogs.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index eb2ebb1958..19c9c52a0a 100644
@@ -292,7 +292,7 @@ class ParseLogsTest(OERuntimeTestCase):
         grepcmd = 'grep '
         grepcmd += '-Ei "'
         for error in errors:
-            grepcmd += error + '|'
+            grepcmd += '\<' + error + '\>' + '|'
         grepcmd = grepcmd[:-1]
         grepcmd += '" ' + str(log) + " | grep -Eiv \'"
 

2.22.0