Sonar: logging arguments should not require evaluation

Passing concatenated strings into a logging method can incur a needless
performance hit because the concatenation will be performed every time
the method is called, whether or not the log level is low enough to show
the message.

Use built-in string formatting instead.

Change-Id: Ifb2c4e6c4f835a7966f4fa51331e1e0d6848e78d