packaging: make python snippets in rpm building python3 compatible

Fedora 31 has Python3 at /usr/bin/python, and buildrpm would fail on snippets
that use python2 syntax. Instead of forcing python2, just accept for the future
while staying backwards compatible.

contrib/packaging/buildrpm

@@ -121,8 +121,8 b' for l in sorted(changelog, reverse=True)'
     if prevtitle != title:
         prevtitle = title
         print
-        print title
-    print "- %s" % l[3].strip()
+        print(title)
+    print("- %s" % l[3].strip())
 ' >> $rpmspec
 
 else
@@ -138,7 +138,7 b' def datestr(date, format):'
 for l in sys.stdin.readlines():
     tok = l.split("\t")
     hgdate = tuple(int(v) for v in tok[0].split())
-    print "* %s %s\n- %s" % (datestr(hgdate, "%a %b %d %Y"), tok[1], tok[2])
+    print("* %s %s\n- %s" % (datestr(hgdate, "%a %b %d %Y"), tok[1], tok[2]))
 ' >> $rpmspec
 
 fi

contrib/packaging/mercurial.spec

@@ -15,7 +15,7 b''
 
 %else
 
-%global pythonver %(python -c 'import sys;print ".".join(map(str, sys.version_info[:2]))')
+%global pythonver %(python -c 'import sys;print(".".join(map(str, sys.version_info[:2])))')
 
 %endif