Apply suggestions from code review

Co-authored-by: bjorn3 <[email protected]>

Author: folkertdev

bzip2.rs

@@ -527,7 +527,7 @@ unsafe fn testStream(zStream: *mut FILE) -> bool {
                 break 'errhandler;
             }
 
-            let mut unusedTmpV: *mut libc::c_void = std::ptr::null_mut::<libc::c_void>();
+            let mut unusedTmpV = std::ptr::null_mut();
             BZ2_bzReadGetUnused(&mut bzerr, bzf, &mut unusedTmpV, &mut nUnused);
             if bzerr != libbzip2_rs_sys::BZ_OK {
                 panic_str("test:bzReadGetUnused");
@@ -552,8 +552,7 @@ unsafe fn testStream(zStream: *mut FILE) -> bool {
         if ferror(zStream) != 0 {
             ioError() // diverges
         }
-        ret = fclose(zStream);
-        if ret == libc::EOF {
+        if fclose(zStream) == libc::EOF {
             ioError() // diverges
         }