gpg: Can't check signature: public key not found错误的解决方法

repo init时报错：
......
object 30d452905f166b316152f236422f85c8aa75a2d0
type commit
tag v1.7.5
tagger Shawn O. Pearce <sop@google.com> 1307663540 -0700

repo 1.7.5

gpg: Signature made Fri 10 Jun 2011 07:52:20 AM CST using DSA key ID 920F5C65
gpg: Can't check signature: public key not found
error: could not verify the tag 'v1.7.5'

出错原因是曾使用repo sync从其它库sync过代码，删掉~/.repoconfig即可：
$ rm -rf ~/.repoconfig
$ ./repo init -u git://github.com/CyanogenMod/android.git -b gingerbread
gpg: keyring `/home/calvin/.repoconfig/gnupg/secring.gpg' created
gpg: keyring `/home/calvin/.repoconfig/gnupg/pubring.gpg' created
gpg: /home/calvin/.repoconfig/gnupg/trustdb.gpg: trustdb created
gpg: key 920F5C65: public key "Repo Maintainer <repo@android.kernel.org>" imported
gpg: Total number processed: 1
gpg:               imported: 1

Getting repo ...
   from http://android.git.kernel.org/tools/repo.git 。。。。