adjust expectations to deal with reqwest Content-Length

In short, reqwest sends a `content-length: 0` header in GET
requests for a reason maybe related to this issue:

seanmonstar/reqwest#1971

For now, let's ignore Content-Length header lines.

Author: Byron

gix-transport/tests/client/blocking_io/http/mod.rs

@@ -337,6 +337,7 @@ fn handshake_v1() -> crate::Result {
             .received_as_string()
             .lines()
             .map(str::to_lowercase)
+            .filter(ignore_reqwest_content_length)
             .collect::<HashSet<_>>(),
         format!(
             "GET /path/not/important/due/to/mock/info/refs?service=git-upload-pack HTTP/1.1
@@ -680,3 +681,7 @@ fn check_content_type_is_case_insensitive() -> crate::Result {
     assert!(result.is_ok());
     Ok(())
 }
+
+fn ignore_reqwest_content_length(header_line: &String) -> bool {
+    header_line != "content-length: 0"
+}