toolbox: android_fork_execvp_ext() requires getattr ioctl

Addresses the following denials:

  avc:  denied  { getattr } for  pid=148 comm="mkswap" path="/dev/pts/0" dev="devpts" ino=3 scontext=u:r:toolbox:s0 tcontext=u:object_r:devpts:s0 tclass=chr_file permissive=1
  avc:  denied  { ioctl } for  pid=148 comm="mkswap" path="/dev/pts/0" dev="devpts" ino=3 scontext=u:r:toolbox:s0 tcontext=u:object_r:devpts:s0 tclass=chr_file permissive=1

Change-Id: I88c88493cd5f523b5b26a8028b421b3565aa5751

toolbox.te

@@ -12,7 +12,7 @@ init_daemon_domain(toolbox)
 allow toolbox tmpfs:chr_file { read write ioctl };
 
 # Inherit and use pty created by android_fork_execvp_ext().
-allow toolbox devpts:chr_file { read write };
+allow toolbox devpts:chr_file { read write getattr ioctl };
 
 # mkswap-specific.
 # Read/write block devices used for swap partitions.