Fix #1210 grep error on MacOS with ssh completion

See #1210

completion/available/ssh.completion.bash

@@ -13,7 +13,7 @@ _sshcomplete() {
 
     # parse all defined hosts from .ssh/config and files included there
     for fl in "$HOME/.ssh/config" \
-        $(grep -P "^\s*Include" "$HOME/.ssh/config" | 
+        $(grep "^\s*Include" "$HOME/.ssh/config" | 
             awk '{for (i=2; i<=NF; i++) print $i}' | 
             sed "s|^~/|$HOME/|")
     do