vold: Fix a few bugs

 - share command was taking wrong arguments
 - shared command was returning two termination codes
 - Force FAT32 cluster size to 4k when formatting
Signed-off-by: San Mehat <san@google.com>
diff --git a/Fat.cpp b/Fat.cpp
index 4f65d38..f934ebc 100644
--- a/Fat.cpp
+++ b/Fat.cpp
@@ -164,15 +164,17 @@
     }
     close(fd);
 
-    const char *args[7];
+    const char *args[9];
     int rc;
     args[0] = MKDOSFS_PATH;
     args[1] = "-F";
     args[2] = "32";
     args[3] = "-O";
     args[4] = "android";
-    args[5] = fsPath;
-    args[6] = NULL;
+    args[5] = "-c";
+    args[6] = "8";
+    args[7] = fsPath;
+    args[8] = NULL;
     rc = logwrap(7, args, 1);
 
     if (rc == 0) {