passthrough: only open /dev/occX during the operation

The file handle was left open constantly, resulting in dead file handles
when FSI is rescanned.

Change-Id: I1ca8b330131eaad3e3672f5e8fbc3b994e8c34d6
Signed-off-by: Eddie James <eajames@us.ibm.com>
diff --git a/occ_pass_through.hpp b/occ_pass_through.hpp
index 205fc04..384a065 100644
--- a/occ_pass_through.hpp
+++ b/occ_pass_through.hpp
@@ -60,6 +60,9 @@
          */
         std::string devicePath;
 
+        /** @brief Indicates whether or not the OCC is currently active */
+        bool occActive = false;
+
         /** brief file descriptor associated with occ device */
         int fd = -1;