lib: raise the minimum Python version from 2.6 to 2.7

As discussed in #1811

PR-URL: #1818
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: João Reis <reis@janeasystems.com>

lib/find-python.js

@@ -19,7 +19,7 @@ PythonFinder.prototype = {
   argsExecutable: [ '-c', 'import sys; print(sys.executable);' ],
   argsVersion: [ '-c', 'import sys; print("%s.%s.%s" % sys.version_info[:3]);' ],
   semverRange: process.env.EXPERIMENTAL_NODE_GYP_PYTHON3 ? '2.7.x || >=3.5.0'
-    : '>=2.6.0 <3.0.0',
+    : '>=2.7.0 <3.0.0',
 
   // These can be overridden for testing:
   execFile: cp.execFile,