syntax-check: sc_avoid_write: Don't use blanket file exceptions

syntax-check: sc_avoid_write: Don't use blanket file exceptions

Adding an exception for the whole file usually defeats the purpose of a
syntax check and is also likely to get forgotten once the file is
removed.

In case of the suggestion of using 'safewrite' instead of write even the
comment for safewrite states that the function needs to be used only in
certain cases.

Remove the blanket exceptions for files and use an exclude string
instead. The only instance where we keep the full file exception is for
src/libvirt-stream.c as there are multiple uses in example code in
comments where I couldn't find a nicer targetted wapproach.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>