include unistd.h to get ssize_t definitions

Fixes errors like

| In file included from plugins/mas.c:36:0:
| ./src/obex.h:39:1: error: unknown type name 'ssize_t'
| ./src/obex.h:49:1: error: unknown type name 'ssize_t'
| ./src/obex.h:50:1: error: unknown type name 'ssize_t'
| In file included from plugins/mas.c:38:0:
| ./src/mimetype.h:36:2: error: expected specifier-qualifier-list before 'ssize_t'
| In file included from plugins/mas.c:39:0:
| plugins/filesystem.h:24:1: error: unknown type name 'ssize_t'
| plugins/mas.c:550:1: error: unknown type name 'ssize_t'
| plugins/mas.c:557:1: error: unknown type name 'ssize_t'
| plugins/mas.c: In function 'any_read':
| plugins/mas.c:560:2: error: unknown type name 'ssize_t'

Upstream-Status: Pending

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Index: obexd-0.44/plugins/mas.c
===================================================================
--- obexd-0.44.orig/plugins/mas.c	2012-01-11 14:53:53.000000000 -0800
+++ obexd-0.44/plugins/mas.c	2013-01-08 12:51:12.681882174 -0800
@@ -29,6 +29,7 @@
 #include <glib.h>
 #include <fcntl.h>
 #include <inttypes.h>
+#include <unistd.h>
 
 #include "obexd.h"
 #include "plugin.h"