Better git fetch (#2626)
Better git fetch (#2626)

Related to https://github.com/FreshRSS/FreshRSS/pull/2625

If for some reasons branches have diverged:, e.g.:

```
$ git status -sb --porcelain remote
## dev...origin/dev [ahead 4, behind 1]
```
romibi/FreshRSS,Alkarex/FreshRSS,romibi/FreshRSS,FreshRSS/FreshRSS,Alkarex/FreshRSS,FreshRSS/FreshRSS,Alkarex/FreshRSS,marienfressinaud/FreshRSS,romibi/FreshRSS,aledeg/FreshRSS,FreshRSS/FreshRSS,marienfressinaud/FreshRSS,FreshRSS/FreshRSS,romibi/FreshRSS,marienfressinaud/FreshRSS,aledeg/FreshRSS,aledeg/FreshRSS,aledeg/FreshRSS,marienfressinaud/FreshRSS,Alkarex/FreshRSS