MergeMappingException exception while importing exported dashboard

[szydan]

master branch

to reproduce:
0) create the indexPattern

1. create a single dashboard with single visualization
2. export all objects to a file
3. delete .kibana index
4. restart kibana
5. create indexPattern
6. Go to Settings->Import and import your exported file
   here everything is fine no error
7. try to switch to Dashboards
   HERE is the error

MergeMappingException[Merge failed with failures {[mapper [version] of different type, current_type [long], merged_type [integer]]}]

I think that the issue is that by default elasticsearch is creating the mapping long for fields like
"version", "hits"
But then in _saved_dashboard.js or other services the mapping contains "integer" type for this properties
so at some point kibana is sending a PUT request to set the mapping
and elasticsearch throws an error as it can't change it from long to integer

The error is gone when I change in the source code (mapping in service classes) all properties which where integer to long

[biolds]

The patch was reverted, see:
#5934
Can we reopen this?