idle-maint: don't need to change discard_granularity

F2FS changes proper configurations along with gc_urgent, so idle-maint doesn't
need to set this redundantly.

Change-Id: I4a71a5d877a3bb9636e2b65132ec806edc56a8fe
Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>
diff --git a/IdleMaint.cpp b/IdleMaint.cpp
index 3ccb806..a2d0f91 100644
--- a/IdleMaint.cpp
+++ b/IdleMaint.cpp
@@ -236,9 +236,6 @@
 static int startGc(const std::list<std::string>& paths) {
     for (const auto& path : paths) {
         LOG(DEBUG) << "Start GC on " << path;
-        if (!WriteStringToFile("1", path + "/discard_granularity")) {
-            PLOG(WARNING) << "Set discard gralunarity failed on" << path;
-        }
         if (!WriteStringToFile("1", path + "/gc_urgent")) {
             PLOG(WARNING) << "Start GC failed on " << path;
         }
@@ -252,9 +249,6 @@
         if (!WriteStringToFile("0", path + "/gc_urgent")) {
             PLOG(WARNING) << "Stop GC failed on " << path;
         }
-        if (!WriteStringToFile("16", path + "/discard_granularity")) {
-            PLOG(WARNING) << "Set discard gralunarity failed on" << path;
-        }
     }
     return android::OK;
 }