dedupe: fix buffer overflow
dedupe: fix buffer overflow

the length of key was incorrect, 4.2's libc detects the overflow
and crashes

Change-Id: I0970848c6c089b86907827ce8242ef7499b12d63

InsomniaAOSP/platform_bootable_recovery,randomblame/bootable_recovery,76Demented/bootable_recovery-,DerTeufel/dualboot_recovery,Plain-Andy/android_platform_bootable_recovery,76Demented/bootable_recovery-,kylinmoddev/android_bootable_recovery,76Demented/bootable_recovery-,DerTeufel/dualboot_recovery,DerTeufel/dualboot_recovery,InsomniaAOSP/platform_bootable_recovery,InsomniaAOSP/platform_bootable_recovery,InsomniaAOSP/platform_bootable_recovery,randomblame/bootable_recovery,kylinmoddev/android_bootable_recovery,DerTeufel/dualboot_recovery,randomblame/bootable_recovery,DerTeufel/dualboot_recovery,randomblame/bootable_recovery,76Demented/bootable_recovery-,kylinmoddev/android_bootable_recovery,Plain-Andy/android_platform_bootable_recovery,76Demented/bootable_recovery-,randomblame/bootable_recovery,Plain-Andy/android_platform_bootable_recovery,kylinmoddev/android_bootable_recovery,Plain-Andy/android_platform_bootable_recovery,InsomniaAOSP/platform_bootable_recovery