[VOL-3117] Read KV store data path prefix from an environment variable

- voltha-lib-go reads the KVStoreDataPrefix from env variable, so removed the command-line flag in voltha-go
- also removed unused corepair topic flag
Change-Id: Ibe8403bf187126b587a92cd9c58aa6d923f84cd0
diff --git a/go.sum b/go.sum
index d66b654..98a0e62 100644
--- a/go.sum
+++ b/go.sum
@@ -196,8 +196,8 @@
 github.com/onsi/ginkgo v1.6.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
 github.com/onsi/gomega v1.4.2 h1:3mYCb7aPxS/RU7TI1y4rkEn1oKmPRjNJLNEXgw7MH2I=
 github.com/onsi/gomega v1.4.2/go.mod h1:ex+gbHU/CVuBBDIJjb2X0qEXbFg53c61hWP/1CpauHY=
-github.com/opencord/voltha-lib-go/v3 v3.1.10 h1:Wo4dsbjp2J2iOSarFSWUM8snqruQ5UoDLnzANMJd69s=
-github.com/opencord/voltha-lib-go/v3 v3.1.10/go.mod h1:26TG6ABl+ppP754YWhhgao9wKNL3SuUf/KztQcJFqrQ=
+github.com/opencord/voltha-lib-go/v3 v3.1.12 h1:ey3mpwB0mOuoK0cnonF6O0cNJlb75ZudqGpGz/50l4k=
+github.com/opencord/voltha-lib-go/v3 v3.1.12/go.mod h1:26TG6ABl+ppP754YWhhgao9wKNL3SuUf/KztQcJFqrQ=
 github.com/opencord/voltha-protos/v3 v3.3.3 h1:OO0H+YMxjLFQifoYXwBp1JN5rpEVMQnhGGEdP6pLrY0=
 github.com/opencord/voltha-protos/v3 v3.3.3/go.mod h1:nl1ETp5Iw3avxOaKD8BJlYY5wYI4KeV95aT1pL63nto=
 github.com/pascaldekloe/goe v0.0.0-20180627143212-57f6aae5913c/go.mod h1:lzWF7FIEvWOWxwDKqyGYQf6ZUaNfKdP144TG7ZOy1lc=