Provide a command ‘hydra-init’ to initialise/upgrade the database

For schema upgrades, hydra-init executes the files
src/sql/upgrade-<N>.sql, each of which upgrades the schema from
version N-1 to N.  The upgrades are wrapped in a transaction.

tests/Makefile.am

@@ -31,7 +31,7 @@ clean :
 check_SCRIPTS = db.sqlite repos
 
 db.sqlite : $(top_srcdir)/src/sql/hydra-sqlite.sql
-	sqlite3 db.sqlite <  $(top_srcdir)/src/sql/hydra-sqlite.sql
+	perl $(top_srcdir)/src/script/hydra-init
 
 repos : dirs git-repo hg-repo svn-repo svn-checkout-repo bzr-repo bzr-checkout-repo