Append SOL log with .txt extension

Request from OP team so that they can view as text from the jenkins
web view.

Resolves  openbmc/openbmc-test-automation#974

Change-Id: Idff4ceb6c501471389d02fd1f07d345ed1981a30
Signed-off-by: George Keishing <gkeishin@in.ibm.com>
diff --git a/lib/utils.robot b/lib/utils.robot
index 851358a..1f74ae2 100755
--- a/lib/utils.robot
+++ b/lib/utils.robot
@@ -495,7 +495,7 @@
     #            keyword will use the caller's file_path value.  In either
     #            case, the value will be returned.
 
-    ${default_file_path}=  Catenate  /tmp/${OPENBMC_HOST}_os_console
+    ${default_file_path}=  Catenate  /tmp/${OPENBMC_HOST}_os_console.txt
     ${log_file_path}=  Set Variable If  '${log_file_path}' == '${EMPTY}'
     ...  ${default_file_path}  ${log_file_path}