Fix zgrep --version

"zgrep --version" is expected to print the version information in the
same way as "zgrep -V". However, the case handling the --version flag
is never reached, so "zgrep --version" prints:
    zgrep: missing pattern
instead of:
    grep (BSD grep, GNU compatible) 2.6.0-FreeBSD

Reviewed by:	yuripv
Approved by:	yuripv (src)
MFC after:	1 week
Differential Revision: https://reviews.freebsd.org/D29813

usr.bin/grep/zgrep.sh

@@ -94,6 +94,9 @@ do
 	    silent=1
 	    shift
 	    ;;
+	-V|--version)
+	    exec ${grep} -V
+	    ;;
 	--*)
 	    grep_args="${grep_args} $1"
 	    shift
@@ -128,9 +131,6 @@ do
 	    echo "${prg}: the ${1} flag is not currently supported" >&2
 	    exit 1
 	    ;;
-	-V|--version)
-	    exec ${grep} -V
-	    ;;
 	-*)
 	    grep_args="${grep_args} $1"
 	    shift