Additional info:

 

[2019-12-13 22:26:58,876] INFO     Installing erp5.
[2019-12-13 22:26:58,876] INFO     Warning: "branch" parameter with value
"master" is ignored. Checking out to revision
80994259537cc30d255d9230aabaf47dce621bf8.
[2019-12-13 22:26:58,876] INFO     Cloning into '/opt/slapgrid/
5b41896bce906eba84123c9581f4751d/parts/erp5'...
[2019-12-13 22:26:58,876] INFO     Checking out files:  17% (14910/83621)
....

.....

Checking out files:  88% (3310/3761)
fatal: not a git repository: ../.git/modules/doc-bt5
[2019-12-13 22:26:58,877] INFO     fatal: could not reset submodule index
[2019-12-13 22:26:58,877] INFO     While:
[2019-12-13 22:26:58,877] INFO       Installing erp5.
[2019-12-13 22:26:58,877] INFO     Error: Impossible to clone repository.