build: remove unsupported Python 2.6 from configure

PR-URL: #27381
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Beth Griggs <Bethany.Griggs@uk.ibm.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Rich Trott <rtrott@gmail.com>

configure

@@ -13,10 +13,10 @@ del _
 
 import sys
 from distutils.spawn import find_executable as which
-if sys.version_info[0] != 2 or sys.version_info[1] not in (6, 7):
-  sys.stderr.write('Please use either Python 2.6 or 2.7')
+if sys.version_info[:2] != (2, 7):
+  sys.stderr.write('Please use Python 2.7')
 
-  python2 = which('python2') or which('python2.6') or which('python2.7')
+  python2 = which('python2') or which('python2.7')
 
   if python2:
     sys.stderr.write(':\n\n')