Backport the bugfix for debug symbols generator (ubuntu#284)

Author: sergio-costas

tools/strip_binaries.py

@@ -41,6 +41,11 @@ def read_elf_type(filepath):
                 for note in sect.iter_notes():
                     if  note['n_type'] == 'NT_GNU_BUILD_ID':
                         buildId = note['n_desc']
+                        # Sometimes, ELFtools return a bytes array instead of a string.
+                        # This fixes it.
+                        # https://github.com/eliben/pyelftools/issues/188
+                        if isinstance(buildId, bytes):
+                            buildId = buildId.hex()
                         break
         except:
             return None, None