build: Update po/POTFILES.in for new/renamed source files

lib/dpkg/dir.c (commit 20fdb395cc721a5060c5623eda956d73ea840a21)
src/infodb.c (commit 9f7f2a958321d41725c0ae7f46c434fe4cbf3c6a)

lib/dpkg/database.c → lib/dpkg/pkg-db.c (commit
ced5ec027285de3f207c0bb7a26e3455503e7e29)

po/POTFILES.in

@@ -5,8 +5,8 @@ lib/dpkg/buffer.c
 lib/dpkg/cleanup.c
 lib/dpkg/command.c
 lib/dpkg/compress.c
-lib/dpkg/database.c
 lib/dpkg/dbmodify.c
+lib/dpkg/dir.c
 lib/dpkg/dump.c
 lib/dpkg/ehandle.c
 lib/dpkg/fields.c
@@ -22,6 +22,7 @@ lib/dpkg/parsehelp.c
 lib/dpkg/path.c
 lib/dpkg/pkg.c
 lib/dpkg/pkg-array.c
+lib/dpkg/pkg-db.c
 lib/dpkg/pkg-format.c
 lib/dpkg/pkg-list.c
 lib/dpkg/pkg-queue.c
@@ -46,6 +47,7 @@ src/enquiry.c
 src/errors.c
 src/filesdb.c
 src/help.c
+src/infodb.c
 src/main.c
 src/packages.c
 src/processarc.c