Revert "Don't forward fetches with sha in want (#1313)"

This reverts commit a22ab2a.

josh-proxy/src/bin/josh-proxy.rs

@@ -111,14 +111,6 @@ fn fetch_needed(
     head_ref: Option<&str>,
     head_ref_resolved: Option<&str>,
 ) -> Result<bool, FetchError> {
-    if let Some(head_ref) = head_ref {
-        if head_ref != "HEAD" && !head_ref.starts_with("refs/") {
-            // If the request is for fetching a sha, don't fetch, as most upstreams
-            // don't support that. The rev should have been fetched previously by reference.
-            return Ok(false);
-        }
-    }
-
     let fetch_timer_ok = {
         if let Some(last) = service.fetch_timers.read()?.get(remote_url) {
             let since = std::time::Instant::now().duration_since(*last);

tests/proxy/clone_sha.t

@@ -54,11 +54,6 @@
 
   $ cd ${TESTTMP}
 
-  $ git ls-remote http://localhost:8002/real_repo.git | tr '\t' ' '
-  bb282e9cdc1b972fffd08fd21eead43bc0c83cb8 HEAD
-  36c6ab9d481503e14a88f783e87f3791aa8cef99 refs/heads/branch-1
-  bb282e9cdc1b972fffd08fd21eead43bc0c83cb8 refs/heads/master
-
 Checks the following:
 
 1) Two different formats for separating origin ref in the remote URL
@@ -135,6 +130,7 @@ Check (2) and (3) but with a branch ref
   |       |   `-- upstream
   |       |       `-- real_repo.git
   |       |           |-- HEAD
+  |       |           |-- bb282e9cdc1b972fffd08fd21eead43bc0c83cb8
   |       |           `-- refs
   |       |               `-- heads
   |       |                   |-- branch-1
@@ -154,5 +150,5 @@ Check (2) and (3) but with a branch ref
           |-- namespaces
           `-- tags
 
-  35 directories, 22 files
+  35 directories, 23 files