Allow dumpstate to read /system/bin executables.

On 64 bit systems, it's necessary to read the /system/bin executables
elf header to determine if it's a 32 bit or 64 bit executable to
contact the correct debuggerd service.

Bug: 17487122
Change-Id: Ica78aa54e5abbb051924166c6808b79b516274fe

dumpstate.te

@@ -100,3 +100,6 @@ allow dumpstate net_data_file:file r_file_perms;
 # Access /data/tombstones.
 allow dumpstate tombstone_data_file:dir r_dir_perms;
 allow dumpstate tombstone_data_file:file r_file_perms;
+
+# Access /system/bin executables to determine type of executable.
+allow dumpstate {drmserver_exec mediaserver_exec sdcardd_exec surfaceflinger_exec}:file r_file_perms;