Disallow input file write access to jdigen.py am: 091ceb2bb2

Original change: https://android-review.googlesource.com/c/platform/external/oj-libjdwp/+/1351023

Change-Id: I6b0be24ad597e4f7bef2830878e1ce7fc2235a5b
diff --git a/etc/jdigen.py b/etc/jdigen.py
index a5ba1a5..d8ce8af 100644
--- a/etc/jdigen.py
+++ b/etc/jdigen.py
@@ -51,7 +51,7 @@
 INSTANCE_FORMAT = '{{ "{key}", "{value}" }},\n'
 
 VALUES = ""
-with open(args[1], 'r+') as inp:
+with open(args[1], 'r') as inp:
   for l in inp.readlines():
     key, value = l.split('=')
     VALUES += INSTANCE_FORMAT.format(key = key.strip(), value = value.strip())