===========
When doing an upgrade, you execute mysql_upgrade. If
mysql_upgrade fails to connect or it connects with a user
without the proper privileges, it will return the error:

    FATAL ERROR: Upgrade failed

which is not very informative.

ANALYSIS
========

In main() and check_version_match(), the condition for
errors are clubbed together and throw the same error msg.
The functions need to be splitted up and the corresponding
error msgs have to be displayed.

FIX
===
Splitted the functions and added the specific error msg.