Fix clean_all.sh

Author: bjorn3

clean_all.sh

@@ -5,6 +5,6 @@ rm -rf target/ build_system/target download/ build/ dist/
 
 # Kept for now in case someone updates their checkout of cg_clif before running clean_all.sh
 # FIXME remove at some point in the future
-rm y.bin y.bin.dSYM y.exe y.pdb
+rm y.bin y.bin.dSYM y.exe y.pdb 2>/dev/null || true
 rm -rf rand/ regex/ simple-raytracer/ portable-simd/ abi-checker/ abi-cafe/
 rm -rf build_sysroot/{sysroot_src/,target/,compiler-builtins/,rustc_version}