librdmacm/cmtime: Exit test on unexpected error

The test tries to check for connection errors and continue if
one occurs.  However, the client and server must be in synch
regarding the number of connections.  Plus, since the goal of
the test is provide accurate timings of CM steps, if an error
occurs, the timings are thrown off.  Finally, the error handling
is insufficient for what it attempts to do.

Just exit the test on error after printing a message, and avoid
giving a reader the idea that errors are handled properly.

Signed-off-by: Sean Hefty <[email protected]>