syntax-check: Disallow plain fork() in src/libvirt.c

The last usage of plain fork() was removed in v0.9.7-rc1~50, but
we forgot to update the syntax-check exemption list accordingly.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

build-aux/syntax-check.mk

@@ -2016,7 +2016,7 @@ exclude_file_name_regexp--sc_prohibit_close = \
 exclude_file_name_regexp--sc_prohibit_empty_lines_at_EOF = \
   (^tests/(virhostcpu|virpcitest)data/|docs/js/.*\.js|docs/fonts/.*\.woff|\.diff|tests/virconfdata/no-newline\.conf$$)
 
-_src2=src/(util/(vircommand|virdaemon)|libvirt|lxc/lxc_controller)
+_src2=src/(util/(vircommand|virdaemon)|lxc/lxc_controller)
 exclude_file_name_regexp--sc_prohibit_fork_wrappers = \
   (^($(_src2)|tests/testutils)\.c$$)