contrib: drop bitcoin-util exception from FORTIFY check

It's got memcpy_chk.

contrib/guix/security-check.py

@@ -123,9 +123,6 @@ def check_ELF_CONTROL_FLOW(binary) -> bool:
 
 def check_ELF_FORTIFY(binary) -> bool:
 
-    # bitcoin-util does not currently contain any fortified functions
-    if 'Bitcoin Core bitcoin-util utility version ' in binary.strings:
-        return True
     # bitcoin wrapper does not currently contain any fortified functions
     if '--monolithic' in binary.strings:
         return True