Remove a duplicate line in collect_defs

Signed-off-by: Michal Terepeta <michal.terepeta@gmail.com>

Author: michalt

crates/ra_hir_def/src/nameres/collector.rs

@@ -45,7 +45,6 @@ pub(super) fn collect_defs(db: &impl DefDatabase, mut def_map: CrateDefMap) -> C
         // If the dependency defines a prelude, we overwrite an already defined
         // prelude. This is necessary to import the "std" prelude if a crate
         // depends on both "core" and "std".
-        let dep_def_map = db.crate_def_map(dep.crate_id);
         if dep_def_map.prelude.is_some() {
             def_map.prelude = dep_def_map.prelude;
         }