cast unicode to allow json dump

IPython/utils/_sysinfo.py

@@ -1,2 +1,2 b''
 # GENERATED BY setup.py
-commit = ""
+commit = u""

IPython/utils/sysinfo.py

@@ -61,8 +61,8 b' def pkg_commit_hash(pkg_path):'
                             cwd=pkg_path, shell=True)
     repo_commit, _ = proc.communicate()
     if repo_commit:
-        return 'repository', repo_commit.strip()
-    return '(none found)', '<not found>'
+        return 'repository', repo_commit.strip().decode('ascii')
+    return '(none found)', u'<not found>'
 
 
 def pkg_info(pkg_path):

setupbase.py

@@ -579,7 +579,7 b' def git_prebuild(pkg_dir, build_cmd=build_py):'
             with open(out_pth, 'w') as out_file:
                 out_file.writelines([
                     '# GENERATED BY setup.py\n',
-                    'commit = "%s"\n' % repo_commit,
+                    'commit = u"%s"\n' % repo_commit,
                 ])
     return require_submodules(MyBuildPy)