Silence Clang Scan warning about use of unitialized variable.

While the warning is a false positive, it is possible to clarify the code by
always initializing the variable. This does also allow to make the sending
of the "beep" control sequence depend on the validity of its parameters.

I have left the redundant assignment of 0 to the now initialized variables
in place since this makes the code simpler to understand and does not add
any run-time overhead (the compiler completely removes the "else if" test
and the assignments).

There was an embedded literal escape character in a string, which messes up
diplaying the source code on a terminal that interprets ANSI sequences. The
literal escape has been replaced by \e (non-standard, but supported by all
relevant compilers, and already used in other source files in base).

MFC after: 2 weeks