[Techsupport] Update the message seen during the lock acquisition failure (sonic-net#2897)

#### What I did

When a second techsupport instance starts while one is running, the message thrown before exiting is not very user friendly. Thus updating the message for it to make more sense.

Author: vivekrnv

scripts/generate_dump

@@ -2074,7 +2074,7 @@ else
         rm_lock_and_exit
     else
         # Lock is valid and the other instance is active. Exit Now
-        echo "Accquiring lock failed, PID ${PID_PROG} is active" >&2
+        echo "Another instance of techsupport running with PID: ${PID_PROG}, please retry after some time..." >&2
         exit $EXT_LOCKFAIL
     fi
 fi