use long key fingerprint to prevent collisions

INSTALL.md

@@ -57,7 +57,7 @@ The stable and the nightly packages are built for Ubuntu Xenial (16.04), Ubuntu
 **Stable and Signed Packages**
 
 ```bash
-sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys D4284CDD
+sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 4052245BD4284CDD
 echo "deb https://repo.iovisor.org/apt/xenial xenial main" | sudo tee /etc/apt/sources.list.d/iovisor.list
 sudo apt-get update
 sudo apt-get install bcc-tools libbcc-examples linux-headers-$(uname -r)