libassuan: drop -unknown suffix from version number

libassuan: drop -unknown suffix from version number

Include drop-unknown-suffix.inc to remove unknown suffix from version in
pc file.

Befor the fix:
$ cat /usr/lib/pkgconfig/libassuan.pc
[snip]
Name: libassuan
Description: IPC library for the GnuPG components
Requires.private: gpg-error
Version: 3.0.2-unknown
Cflags: -I${includedir}
[snip]

After the fix:
$ cat /usr/lib/pkgconfig/libassuan.pc
[snip]
Name: libassuan
Description: IPC library for the GnuPG components
Requires.private: gpg-error
Version: 3.0.2
Cflags: -I${includedir}
[snip]

Signed-off-by: Yi Zhao <yi.zhao@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>