_scripts: fix latestver.py (#2756)

Fix latestver to sort rc and beta versions before normal releases.

_scripts/latestver.py

@@ -2,11 +2,25 @@
 import json
 import urllib
 import sys
-from distutils.version import LooseVersion
+import re
+
+def splitver(x):
+	v = re.split(r'([^\d]+)', x)
+	v[0] = int(v[0])
+	if len(v) > 2:
+		v[2] = int(v[2])
+	if len(v) > 4:
+		v[4] = int(v[4])
+	# make rc/beta versions sort before normal versions
+	if len(v) > 3 and v[3] == '.':
+		v[3] = '~' 
+	elif len(v) == 3:
+		v.append('~')
+	return v
 
 ver = sys.argv[1]
 d = json.loads(urllib.urlopen('https://golang.org/dl/?mode=json&include=all').read())
-ds = sorted(d, reverse=True, key=lambda it: LooseVersion(it['version'][2:]))
+ds = sorted(d, reverse=True, key=lambda it: splitver(it['version'][2:]))
 for x in ds:
 	if x['version'][:len(ver)] == ver:
 		print x['version']