debian: Make the package creation work on debian squeeze (stable)

the dh_autoreconf application did not honor the sourcedirectory
option back then. Override the target and call autoreconf from
the right directory.
The libdbi development package is called libdbi0-dev. Use this name
for Debian stable but it should work for Ubuntu as well.
diff --git a/debian/control b/debian/control
index d9b3473..e0d75aa 100644
--- a/debian/control
+++ b/debian/control
@@ -2,7 +2,7 @@
 Section: net
 Priority: optional
 Maintainer: Harald Welte <laforge@gnumonks.org>
-Build-Depends: debhelper (>= 7.0.0~), autotools-dev, pkg-config, libgtp-dev, libosmocore-dev, libosmo-sccp-dev, libdbi-dev, dh-autoreconf, libosmo-abis-dev, libdbd-sqlite3
+Build-Depends: debhelper (>= 7.0.0~), autotools-dev, pkg-config, libgtp-dev, libosmocore-dev, libosmo-sccp-dev, libdbi0-dev, dh-autoreconf, libosmo-abis-dev, libdbd-sqlite3
 Standards-Version: 3.8.4
 Homepage: http://openbsc.osmocom.org/
 Vcs-Git: git://bs11-abis.gnumonks.org/openbsc.git