Make sure we properly usleep() on windows rmdir/unlink

usleep() returns void, therefore the previous code didn't work

src/Composer/Util/Filesystem.php

@@ -199,9 +199,15 @@ class Filesystem
      */
     public function unlink($path)
     {
-        if (!@$this->unlinkImplementation($path)) {
+        $unlinked = @$this->unlinkImplementation($path);
+        if (!$unlinked) {
             // retry after a bit on windows since it tends to be touchy with mass removals
-            if (!Platform::isWindows() || (usleep(350000) && !@$this->unlinkImplementation($path))) {
+            if (Platform::isWindows()) {
+                usleep(350000);
+                $unlinked = @$this->unlinkImplementation($path);
+            }
+            
+            if (!$unlinked) {
                 $error = error_get_last();
                 $message = 'Could not delete '.$path.': ' . @$error['message'];
                 if (Platform::isWindows()) {
@@ -224,9 +230,15 @@ class Filesystem
      */
     public function rmdir($path)
     {
-        if (!@rmdir($path)) {
+        $deleted = @rmdir($path);
+        if (!$deleted) {
             // retry after a bit on windows since it tends to be touchy with mass removals
-            if (!Platform::isWindows() || (usleep(350000) && !@rmdir($path))) {
+            if (Platform::isWindows()) {
+                usleep(350000);
+                $deleted = !@rmdir($path);
+            }
+            
+            if (!$deleted) {
                 $error = error_get_last();
                 $message = 'Could not delete '.$path.': ' . @$error['message'];
                 if (Platform::isWindows()) {