debian: Make the -dev package depend on the normal one

Make libosmocore-dev depend on libosmocore. Otherwise
we only end up with the libosmocore.a files installed
and then have various issues with the link order when
linking OpenBSC and such.
diff --git a/debian/control b/debian/control
index 164fc38..3f92875 100644
--- a/debian/control
+++ b/debian/control
@@ -17,7 +17,7 @@
 Package: libosmocore-dev
 Section: libdevel
 Architecture: any
-Depends: ${shlibs:Depends}, ${misc:Depends}
+Depends: ${shlibs:Depends}, ${misc:Depends}, libosmocore
 Description: Development headers for Open Source MObile COMmunications CORE library
 
 #Package: libosmocore-dbg