Simplify database_connection_url

* does not expects dynamic scoping.
* does not uses eval.

Change-Id: I5ba4e5b7ffaabbb3c2bddadf9e53a2875de8b7c0
diff --git a/lib/databases/postgresql b/lib/databases/postgresql
index 2c37f49..7d4a6c5 100644
--- a/lib/databases/postgresql
+++ b/lib/databases/postgresql
@@ -70,9 +70,8 @@
 }
 
 function database_connection_url_postgresql {
-    local output=$1
-    local db=$2
-    eval "$output=$BASE_SQL_CONN/$db?client_encoding=utf8"
+    local db=$1
+    echo "$BASE_SQL_CONN/$db?client_encoding=utf8"
 }
 
 # Restore xtrace