Fix elf regression for python3

Author: Arusekk

pwnlib/elf/elf.py

@@ -792,7 +792,7 @@ def _patch_elf_and_read_maps(self):
         try:
             with context.silent:
                 io = process(path)
-                data = io.recvall(timeout=2)
+                data = context._decode(io.recvall(timeout=2))
         except Exception:
             log.warn_once("Injected /proc/self/maps code did not execute correctly")
             return {}