ITS#8529 Avoid hiding the error if user specified CA does not load

ITS#8529 Avoid hiding the error if user specified CA does not load

The TLS configuration deliberately hid the error in case that
user specified CA locations cannot be read, by loading CAs from default
locations; and when user does not specify CA locations, the CAs from default
locations are not read at all.

This patch corrects the behaviour so that CAs from default location are used
if user does not specify a CA location, and user is informed of the error if
CAs cannot be loaded from the user specified location.