Fix checking bad dns seeds without casting

Since seed lines comes with 'str' type, comparing it directly with 0
('int' type) in the if statement was not working at all. This is fixed
by casting 'int' type to the values in the 'good' column of seeds text file.

Lines that starts with comment in the seeds text file are now ignored.

If statement for checking bad seeds are moved to the top of the 'parseline'
function as if seed is bad, there is no point of going forward from there.

contrib/seeds/makeseeds.py

@@ -46,10 +46,16 @@ def parseline(line: str) -> Union[dict, None]:
     """ Parses a line from `seeds_main.txt` into a dictionary of details for that line.
     or `None`, if the line could not be parsed.
     """
+    if line.startswith('#'):
+        # Ignore line that starts with comment
+        return None
     sline = line.split()
     if len(sline) < 11:
         # line too short to be valid, skip it.
         return None
+    # Skip bad results.
+    if int(sline[1]) == 0:
+        return None
     m = PATTERN_IPV4.match(sline[0])
     sortkey = None
     ip = None
@@ -83,9 +89,6 @@ def parseline(line: str) -> Union[dict, None]:
         sortkey = ip
         ipstr = m.group(1)
         port = int(m.group(6))
-    # Skip bad results.
-    if sline[1] == 0:
-        return None
     # Extract uptime %.
     uptime30 = float(sline[7][:-1])
     # Extract Unix timestamp of last success.