virsh: Add completer for '--type' option of 'attach-interface' command

The '--type' option of 'attach-interface' command is translated
from string into int using virDomainNetTypeFromString(), IOW the
expected value is from virDomainNetType enum.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>

tools/virsh-completer-domain.c

@@ -35,6 +35,7 @@
 #include "virkeynametable_linux.h"
 #include "virkeynametable_osx.h"
 #include "virkeynametable_win32.h"
+#include "conf/domain_conf.h"
 #include "conf/storage_conf.h"
 #include "conf/numa_conf.h"
 
@@ -1119,3 +1120,15 @@ virshDomainDirtyRateCalcModeCompleter(vshControl *ctl G_GNUC_UNUSED,
     return vshEnumComplete(VIRSH_DOMAIN_DIRTYRATE_CALC_MODE_LAST,
                            virshDomainDirtyRateCalcModeTypeToString);
 }
+
+
+char **
+virshDomainNetTypeCompleter(vshControl *ctl G_GNUC_UNUSED,
+                            const vshCmd *cmd G_GNUC_UNUSED,
+                            unsigned int flags)
+{
+    virCheckFlags(0, NULL);
+
+    return vshEnumComplete(VIR_DOMAIN_NET_TYPE_LAST,
+                           virDomainNetTypeToString);
+}

tools/virsh-completer-domain.h

@@ -199,3 +199,8 @@ char **
 virshDomainDirtyRateCalcModeCompleter(vshControl *ctl,
                                       const vshCmd *cmd,
                                       unsigned int flags);
+
+char **
+virshDomainNetTypeCompleter(vshControl *ctl,
+                            const vshCmd *cmd,
+                            unsigned int flags);

tools/virsh-domain.c

@@ -837,6 +837,7 @@ static const vshCmdOptDef opts_attach_interface[] = {
      .type = VSH_OT_STRING,
      .positional = true,
      .required = true,
+     .completer = virshDomainNetTypeCompleter,
      .help = N_("network interface type")
     },
     {.name = "source",