Remove repeated includes

In pty.c there was both an include of our pty.h and the system installed pty.h.
The latter contains only two functions openpty and forkpty. We use neither so
I assume it was a typo and removed it. We still compile and pass all tests.

src/bus-proxyd/bus-proxyd.c

@@ -40,7 +40,6 @@
 #include "bus-internal.h"
 #include "bus-message.h"
 #include "bus-util.h"
-#include "bus-internal.h"
 #include "build.h"
 #include "strv.h"
 #include "def.h"

src/bus-proxyd/test-bus-policy.c

@@ -36,7 +36,6 @@
 #include "bus-internal.h"
 #include "bus-message.h"
 #include "bus-util.h"
-#include "bus-internal.h"
 #include "build.h"
 #include "strv.h"
 #include "def.h"

src/shared/locale-util.c

@@ -25,7 +25,6 @@
 #include "util.h"
 #include "utf8.h"
 #include "strv.h"
-#include "util.h"
 
 #include "locale-util.h"
 

src/shared/missing.h

@@ -33,7 +33,6 @@
 #include <linux/input.h>
 #include <linux/if_link.h>
 #include <linux/loop.h>
-#include <linux/if_link.h>
 
 #ifdef HAVE_AUDIT
 #include <libaudit.h>

src/shared/pty.c

@@ -46,7 +46,6 @@
 #include <fcntl.h>
 #include <limits.h>
 #include <linux/ioctl.h>
-#include <pty.h>
 #include <signal.h>
 #include <stdbool.h>
 #include <stdint.h>

src/sysv-generator/sysv-generator.c

@@ -31,7 +31,6 @@
 #include "path-util.h"
 #include "path-lookup.h"
 #include "log.h"
-#include "strv.h"
 #include "unit.h"
 #include "unit-name.h"
 #include "special.h"