Enhance the syslib library

Enhance syslib/utils_os.robot by
  - Adding messages to the "Should Be Equal" keywords.
  - Enhancing the "Is HTX Running" keyword to return status
    rather than terminating the run.
  - Update the systest/* tests to use the revised
    "Is HTX Running" keyword.
  - Display BMC error logs before termination.

Resolves openbmc/openbmc-test-automation#1304
Change-Id: I17ab8d2deafbe1ef2a232d8356e78740b1b20991
Signed-off-by: Steven Sombar <ssombar@us.ibm.com>
diff --git a/systest/network_stability_test.robot b/systest/network_stability_test.robot
index da09939..5194a71 100755
--- a/systest/network_stability_test.robot
+++ b/systest/network_stability_test.robot
@@ -82,7 +82,7 @@
     Tool Exist  htxcmdline
 
     # Shutdown if HTX is running.
-    ${status}=  Run Keyword And Return Status  Is HTX Running
+    ${status}=  Is HTX Running
     Run Keyword If  '${status}' == 'True'
     ...  Shutdown HTX Exerciser