Enhanced user identity information loading rate

For SRX300 Series devices with eUSB (SRX300, SRX320, SRX340, and SRX345), the authentication entry database moves from disk memory to internal memory. This enhancement reduces disk usage and increases the read-write speed of loading authentication entries. For SRX1500, SRX380, SRX300, SRX320, SRX340, SRX345, SRX4100, SRX4200, SRX4600, SRX550HM, SRX5400, SRX5600, SRX5800 devices and vSRX 3.0 instances, the user firewall database operations on disk are enhanced; this results in reduced disk usage and increases disk lifetime.