Rollup merge of rust-lang#22539 - oli-obk:style_nitpicks, r=Manishearth

 I tried to follow [the style guide][1] as much as possible. This is just from some random readings of the code, so no guarantees on completeness, even in the edited files.

[1]: http://aturon.github.io/style/README.html

Author: Manishearth

src/libcollections/btree/map.rs

@@ -347,7 +347,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
             let result = stack.with(move |pusher, node| {
                 // Same basic logic as found in `find`, but with PartialSearchStack mediating the
                 // actual nodes for us
-                return match Node::search(node, &key) {
+                match Node::search(node, &key) {
                     Found(mut handle) => {
                         // Perfect match, swap the values and return the old one
                         mem::swap(handle.val_mut(), &mut value);
@@ -372,7 +372,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
                 }
             });
             match result {
-                Finished(ret) => { return ret; },
+                Finished(ret) => return ret,
                 Continue((new_stack, renewed_key, renewed_val)) => {
                     stack = new_stack;
                     key = renewed_key;
@@ -439,7 +439,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
         let mut stack = stack::PartialSearchStack::new(self);
         loop {
             let result = stack.with(move |pusher, node| {
-                return match Node::search(node, key) {
+                match Node::search(node, key) {
                     Found(handle) => {
                         // Perfect match. Terminate the stack here, and remove the entry
                         Finished(Some(pusher.seal(handle).remove()))
@@ -1560,7 +1560,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
         let mut stack = stack::PartialSearchStack::new(self);
         loop {
             let result = stack.with(move |pusher, node| {
-                return match Node::search(node, &key) {
+                match Node::search(node, &key) {
                     Found(handle) => {
                         // Perfect match
                         Finished(Occupied(OccupiedEntry {

src/librustc/metadata/loader.rs

@@ -736,12 +736,10 @@ fn get_metadata_section_imp(is_osx: bool, filename: &Path) -> Result<MetadataBlo
             }
         };
         return match ArchiveMetadata::new(archive).map(|ar| MetadataArchive(ar)) {
-            None => {
-                return Err((format!("failed to read rlib metadata: '{}'",
-                                    filename.display())))
-            }
-            Some(blob) => return Ok(blob)
-        }
+            None => Err(format!("failed to read rlib metadata: '{}'",
+                                filename.display())),
+            Some(blob) => Ok(blob)
+        };
     }
     unsafe {
         let buf = CString::new(filename.as_vec()).unwrap();
@@ -791,7 +789,7 @@ fn get_metadata_section_imp(is_osx: bool, filename: &Path) -> Result<MetadataBlo
             }
             llvm::LLVMMoveToNextSection(si.llsi);
         }
-        return Err(format!("metadata not found: '{}'", filename.display()));
+        Err(format!("metadata not found: '{}'", filename.display()))
     }
 }