Remove stale overwritefree flag.

Change-Id: If14998128245245c908b2390acfe28b82339f8bf
diff --git a/vm/Globals.h b/vm/Globals.h
index 5341d26..90e9e88 100644
--- a/vm/Globals.h
+++ b/vm/Globals.h
@@ -119,7 +119,6 @@
      * GC option flags.
      */
     bool        preciseGc;
-    bool        overwriteFree;
     bool        preVerify;
     bool        postVerify;
     bool        generateRegisterMaps;
diff --git a/vm/Init.c b/vm/Init.c
index 06ceabc..6c8ec9e 100644
--- a/vm/Init.c
+++ b/vm/Init.c
@@ -115,7 +115,6 @@
     dvmFprintf(stderr, "  -Xdeadlockpredict:{off,warn,err,abort}\n");
     dvmFprintf(stderr, "  -Xstacktracefile:<filename>\n");
     dvmFprintf(stderr, "  -Xgc:[no]precise\n");
-    dvmFprintf(stderr, "  -Xgc:[no]overwritefree\n");
     dvmFprintf(stderr, "  -Xgc:[no]preverify\n");
     dvmFprintf(stderr, "  -Xgc:[no]postverify\n");
     dvmFprintf(stderr, "  -Xgc:[no]concurrent\n");
@@ -975,10 +974,6 @@
                 gDvm.preciseGc = true;
             else if (strcmp(argv[i] + 5, "noprecise") == 0)
                 gDvm.preciseGc = false;
-            else if (strcmp(argv[i] + 5, "overwritefree") == 0)
-                gDvm.overwriteFree = true;
-            else if (strcmp(argv[i] + 5, "nooverwritefree") == 0)
-                gDvm.overwriteFree = false;
             else if (strcmp(argv[i] + 5, "preverify") == 0)
                 gDvm.preVerify = true;
             else if (strcmp(argv[i] + 5, "nopreverify") == 0)