avoid fs_mkdirs when SD card removed

Must limit vold calls to fs_mkdirs() only when the volume is mounted.
If NOT, it will trigger selinux warning as follows.
audit(1398835637.785:8): avc:  denied  { write } for  pid=137 comm="vold" name="sdcard0" dev="rootfs" ino=3191 scontext=u:r:vold:s0 tcontext=u:object_r:rootfs:s0 tclass=dir

Change-Id: I1113fc961cbdd8bbd2fcbf740c2f504628c8399d
Signed-off-by: Cylen Yao <cylen.yao@mediatek.com>
diff --git a/VolumeManager.cpp b/VolumeManager.cpp
index 1ffa939..2049706 100644
--- a/VolumeManager.cpp
+++ b/VolumeManager.cpp
@@ -1708,20 +1708,20 @@
 }
 
 int VolumeManager::mkdirs(char* path) {
-    // Require that path lives under a volume we manage
+    // Require that path lives under a volume we manage and is mounted
     const char* emulated_source = getenv("EMULATED_STORAGE_SOURCE");
     const char* root = NULL;
     if (emulated_source && !strncmp(path, emulated_source, strlen(emulated_source))) {
         root = emulated_source;
     } else {
         Volume* vol = getVolumeForFile(path);
-        if (vol) {
+        if (vol && vol->getState() == Volume::State_Mounted) {
             root = vol->getMountpoint();
         }
     }
 
     if (!root) {
-        SLOGE("Failed to find volume for %s", path);
+        SLOGE("Failed to find mounted volume for %s", path);
         return -EINVAL;
     }