use python2 not python, cause python is python3

tools/esptool.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python2
 #
 # ESP8266 ROM Bootloader Utility
 # https://github.com/themadinventor/esptool
@@ -8,8 +8,8 @@
 # This program is free software; you can redistribute it and/or modify it under
 # the terms of the GNU General Public License as published by the Free Software
 # Foundation; either version 2 of the License, or (at your option) any later version.
-# 
-# This program is distributed in the hope that it will be useful, but WITHOUT 
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
 # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 # FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 #
@@ -286,7 +286,7 @@ def flash_erase(self):
         # It it on the other hand unlikely to fail.
 
 class ESPFirmwareImage:
-    
+
     def __init__(self, filename = None):
         self.segments = []
         self.entrypoint = 0
@@ -296,11 +296,11 @@ def __init__(self, filename = None):
         if filename is not None:
             f = file(filename, 'rb')
             (magic, segments, self.flash_mode, self.flash_size_freq, self.entrypoint) = struct.unpack('<BBBBI', f.read(8))
-            
+
             # some sanity check
             if magic != ESPROM.ESP_IMAGE_MAGIC or segments > 16:
                 raise Exception('Invalid firmware image')
-        
+
             for i in xrange(segments):
                 (offset, size) = struct.unpack('<II', f.read(8))
                 if offset > 0x40200000 or offset < 0x3ffe0000 or size > 65536:
@@ -458,8 +458,8 @@ def arg_auto_int(x):
             'make_image',
             help = 'Create an application image from binary files')
     parser_make_image.add_argument('output', help = 'Output image file')
-    parser_make_image.add_argument('--segfile', '-f', action = 'append', help = 'Segment input file') 
-    parser_make_image.add_argument('--segaddr', '-a', action = 'append', help = 'Segment base address', type = arg_auto_int) 
+    parser_make_image.add_argument('--segfile', '-f', action = 'append', help = 'Segment input file')
+    parser_make_image.add_argument('--segaddr', '-a', action = 'append', help = 'Segment base address', type = arg_auto_int)
     parser_make_image.add_argument('--entrypoint', '-e', help = 'Address of entry point', type = arg_auto_int, default = 0)
 
     parser_elf2image = subparsers.add_parser(