refactor: fix legacy problems in cmd/serv.go (#38505)

1. use var names "reqOwnerName, reqRepoName", because these values are
from request and should not be really used for path construction
2. simplify enable-pprof logic, don't "log.Fatal"
3. don't make runServe command to guess the repo storage path, instead,
let server return RepoStoragePath
4. don't process lfs verbs when the repo is a wiki
5. construct the request URI path correctly for the lfs transfer backend
(moved to the caller)
6. don't call "owner, err := user_model.GetUserByName", the "owner
rename redirection" has been done before
7. fix incorrect "repo.OwnerName = ownerName", the real owner might have
been "redirected"
8. fix incorrect "inactive owner" check, it should be checked even if
the repo is redirected


Use general error functions to handle responses, error handling code is
hugely simplified.

models/repo/repo.go

@@ -230,7 +230,7 @@ func RelativePath(ownerName, repoName string) string {
 	return strings.ToLower(ownerName) + "/" + strings.ToLower(repoName) + ".git"
 }
 
-// RelativePath should be an unix style path like username/reponame.git
+// RelativePath should be a unix style path like "owner-name/repo-name.git"
 func (repo *Repository) RelativePath() string {
 	return RelativePath(repo.OwnerName, repo.Name)
 }

models/repo/wiki.go

@@ -79,8 +79,8 @@ func RelativeWikiPath(ownerName, repoName string) string {
 	return strings.ToLower(ownerName) + "/" + strings.ToLower(repoName) + ".wiki.git"
 }
 
-// WikiStorageRepo returns the storage repo for the wiki
-// The wiki repository should have the same object format as the code repository
+// WikiStorageRepo returns the storage repo for the wiki like "owner-name/repo-name.wiki.git"
+// The wiki repository should have the same object format as the code repository. TODO: REALLY? Why?
 func (repo *Repository) WikiStorageRepo() StorageRepo {
 	return StorageRepo(RelativeWikiPath(repo.OwnerName, repo.Name))
 }