vsh: Introduce wrapper for add_history()

This allows us to drop include of readline header files from
virsh.c and virt-admin.c because they needed it only because of
the add_history() function.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>

tools/virt-admin.c

@@ -24,11 +24,6 @@
 #include <unistd.h>
 #include <getopt.h>
 
-#if WITH_READLINE
-# include <readline/readline.h>
-# include <readline/history.h>
-#endif
-
 #include "internal.h"
 #include "virt-admin.h"
 #include "viralloc.h"
@@ -1597,9 +1592,8 @@ main(int argc, char **argv)
             if (ctl->cmdstr == NULL)
                 break;          /* EOF */
             if (*ctl->cmdstr) {
-#if WITH_READLINE
-                add_history(ctl->cmdstr);
-#endif
+                vshReadlineHistoryAdd(ctl->cmdstr);
+
                 if (vshCommandStringParse(ctl, ctl->cmdstr, NULL))
                     vshCommandRun(ctl, ctl->cmd);
             }