Clear security sensitive data

As password is sensitive data Clear after use.

Tested:
Verified using ipmitool commands
Command: ipmitool user set password 5 asdf1234 //Set user password
Response: Set User Password command successful (user 5)
Command: ipmitool raw 6 0x47 5 2 0x30 0x70 0x65 0x6e 0x42 0x6d 0x63
         0x31 0 0 0 0 0 0 0 0   //set user password - set password
Response:                //Success
Command: ipmitool raw 6 0x47 5 3 0x30 0x70 0x65 0x6e 0x42 0x6d 0x63
         0x31 0 0 0 0 0 0 0 0  //set user password - test password
Response:                //Success

Signed-off-by: Jayaprakash Mutyala <mutyalax.jayaprakash@intel.com>
Change-Id: I06196233ac5468534bd10fd34f99f7d35fd7b971
diff --git a/user_channel/passwd_mgr.cpp b/user_channel/passwd_mgr.cpp
index b2d32e8..63a226e 100644
--- a/user_channel/passwd_mgr.cpp
+++ b/user_channel/passwd_mgr.cpp
@@ -260,6 +260,8 @@
 
     // Update the timestamp
     fileLastUpdatedTime = getUpdatedFileTime();
+    // Clear sensitive data
+    OPENSSL_cleanse(dataBuf.data(), dataBuf.size());
     return;
 }