Fix file lock issue in androidkindlekey.py

CHANGELOG.md

@@ -103,3 +103,5 @@ This is v10.0.9, a release candidate for v10.1.0. I don't expect there to be maj
 - Fix a bug where decrypting a 256-bit AES pdf with V=5 didn't work.
 - Fix bugs in kgenpids.py, alfcrypto.py, mobidedrm.py and kindlekey.py that caused it to fail on Python 2 (#380).
 - Fix some bugs (Python 2 and Python 3) in erdr2pml.py (untested).
+- Fix file lock bug in androidkindlekey.py on Windows with Calibre >= 7 (untested).
+

DeDRM_plugin/androidkindlekey.py

@@ -201,6 +201,9 @@ def get_serials2(path=STORAGE2):
         for y in tokens:
             serials.append(y)
             serials.append(x+y)
+
+    connection.close()
+
     return serials
 
 def get_serials(path=STORAGE):