convert: handle comments starting with '#' in authormap files

hgext/convert/convcmd.py

@@ -198,7 +198,8 b' class converter(object):'
         afile = open(authorfile, 'r')
         for line in afile:
 
-            if line.strip() == '':
+            line = line.strip()
+            if not line or line.startswith('#'):
                 continue
 
             try:

tests/test-convert-authormap

@@ -16,6 +16,7 b' cd ..'
 cat > authormap.txt <<EOF
 user name = Long User Name
 
+# comment
 this line is ignored
 EOF