Remove unnecessary debug/info logs of normal API ops

There are some debug/info log messages about normal API operations
in each API method, but Nova WSGI framework has already output the
similar messages. So these messages are meaningless, and this patch
removes them.

Change-Id: Ifea3edd912ec80eed2869c3f97345d403ea96c89
Merge "Remove unnecessary debug/info logs of normal API ops"