[FIX] Add necessary dependencies for date_range used by mis_builder

.travis.yml

@@ -2,6 +2,7 @@ sudo: false
 cache: pip
 
 addons:
+  postgresql: "9.2" # minimal postgresql version for the daterange method
   apt:
    sources:
       - pov-wkhtmltopdf

oca_dependencies.txt

@@ -1,3 +1,4 @@
 # list the OCA project dependencies, one per line
 # add a github url if you need a forked version
 reporting-engine
+server-tools