virnetdevtap: Don't check for flags in virNetDevTapCreateFlags

With latest gnulib we are checking even the lowest level functions
whether they check flags. Moreover, we are shadowing the real error
on system without TUNSETIFF support.

cfg.mk

@@ -747,7 +747,7 @@ exclude_file_name_regexp--sc_avoid_write = \
 
 exclude_file_name_regexp--sc_bindtextdomain = ^(tests|examples)/
 
-exclude_file_name_regexp--sc_flags_usage = ^docs/
+exclude_file_name_regexp--sc_flags_usage = ^(docs/|src/util/virnetdevtap\.c$$)
 
 exclude_file_name_regexp--sc_libvirt_unmarked_diagnostics = \
   ^src/rpc/gendispatch\.pl$$

src/util/virnetdevtap.c

@@ -129,14 +129,12 @@ virNetDevProbeVnetHdr(int tapfd)
  */
 int virNetDevTapCreate(char **ifname,
                        int *tapfd,
-                       unsigned int flags)
+                       unsigned int flags ATTRIBUTE_UNUSED)
 {
     int fd;
     struct ifreq ifr;
     int ret = -1;
 
-    virCheckFlags(VIR_NETDEV_TAP_CREATE_VNET_HDR, -1);
-
     if ((fd = open("/dev/net/tun", O_RDWR)) < 0) {
         virReportSystemError(errno, "%s",
                              _("Unable to open /dev/net/tun, is tun module loaded?"));
@@ -239,9 +237,8 @@ cleanup:
 #else /* ! TUNSETIFF */
 int virNetDevTapCreate(char **ifname ATTRIBUTE_UNUSED,
                        int *tapfd ATTRIBUTE_UNUSED,
-                       unsigned int flags)
+                       unsigned int flags ATTRIBUTE_UNUSED)
 {
-    virCheckFlags(0, -1);
     virReportSystemError(ENOSYS, "%s",
                          _("Unable to create TAP devices on this platform"));
     return -1;