Use our own sqlite3: mozilla.d.n's squeeze-backports has dropped it.

config/chroot_apt/preferences

@@ -95,10 +95,6 @@ Package: libstring-formatter-perl
 Pin: origin backports.debian.org
 Pin-Priority: 999
 
-Package: libsqlite3-0
-Pin: origin mozilla.debian.net
-Pin-Priority: 999
-
 Package: libsys-statistics-linux-perl
 Pin: origin backports.debian.org
 Pin-Priority: 999
@@ -303,10 +299,6 @@ Package: spice-vdagent
 Pin: release o=Debian,n=wheezy
 Pin-Priority: 999
 
-Package: sqlite3
-Pin: origin mozilla.debian.net
-Pin-Priority: 999
-
 Package: tor
 Pin: origin deb.torproject.org
 Pin-Priority: 999