build: fix build for Debian 9 and Debian 10

Type: fix

Change-Id: Ic07d0ae313b32e420ba93693cb75960a86f752a9
Signed-off-by: Benoît Ganne <bganne@cisco.com>
(cherry picked from commit 3f0ae664faf33578515ffa1fd5287ad692f16c6f)

1 files changed, 5 insertions, 4 deletions

diff --git a/src/tools/vppapigen/vppapigen.py b/src/tools/vppapigen/vppapigen.py
index 9d74a5b0357..bfc77ca7019 100755
--- a/src/tools/vppapigen/vppapigen.py
+++ b/src/tools/vppapigen/vppapigen.py
@@ -11,7 +11,7 @@ import os
 import sys
 from subprocess import Popen, PIPE
 
-assert sys.version_info >= (3, 6), \
+assert sys.version_info >= (3, 5), \
     "Not supported Python version: {}".format(sys.version)
 log = logging.getLogger('vppapigen')
 
@@ -780,12 +780,13 @@ class VPPAPI(object):
 
     def parse_filename(self, filename, debug=0):
         if self.revision:
-            git_show = f'git show  {self.revision}:{filename}'
+            git_show = 'git show {}:{}'.format(self.revision, filename)
             proc = Popen(git_show.split(), stdout=PIPE, encoding='utf-8')
             try:
                 data, errs = proc.communicate()
                 if proc.returncode != 0:
-                    print(f'File not found: {self.revision}:{filename}', file=sys.stderr)
+                    print('File not found: {}:{}'.format(self.revision,
+                      filename), file=sys.stderr)
                     sys.exit(2)
                 return self.parse_string(data, debug=debug)
             except Exception as e:
@@ -795,7 +796,7 @@ class VPPAPI(object):
                 with open(filename, encoding='utf-8') as fd:
                     return self.parse_fd(fd, None)
             except FileNotFoundError:
-                print(f'File not found: {filename}', file=sys.stderr)
+                print('File not found: {}'.format(filename), file=sys.stderr)
                 sys.exit(2)
 
     def autoreply_block(self, name, parent):