Change how File/Directory/Link .delete works.

runtime/bin/file_linux.cc

Index: runtime/bin/file_linux.cc
diff --git a/runtime/bin/file_linux.cc b/runtime/bin/file_linux.cc
index ceac63052bb2967dc5d10b1c465c74e7f7738ec1..8126ff98179e78227958069d1f0c2b09ebc6b4c0 100644
--- a/runtime/bin/file_linux.cc
+++ b/runtime/bin/file_linux.cc
@@ -167,11 +167,25 @@ bool File::CreateLink(const char* name, const char* target) {
 
 
 bool File::Delete(const char* name) {
-  int status = TEMP_FAILURE_RETRY(remove(name));
-  if (status == -1) {
-    return false;
+  File::Type type = File::GetType(name, true);
+  if (type == kIsFile) {
+    return TEMP_FAILURE_RETRY(unlink(name)) == 0;
+  } else if (type == kIsDirectory) {
+    errno = EISDIR;
+  } else {
+    errno = ENOENT;
+  }
+  return false;
+}
+
+
+bool File::DeleteLink(const char* name) {
+  File::Type type = File::GetType(name, false);
+  if (type == kIsLink) {
+    return TEMP_FAILURE_RETRY(unlink(name)) == 0;
   }
-  return true;
+  errno = EINVAL;
+  return false;
 }