osx: fix build when binary list is not fully compiled.

It can happen that the $binary_list contains apps that are not compiled
(eg. for the lack of a lib). In this case the binary can't be added to
the package. Fixed checking that the binary going to be signed is present.

Change-Id: Iefd9438de972302523ba28596e905b11513a4fea
Reviewed-on: https://code.wireshark.org/review/11968
Reviewed-by: Gerald Combs <gerald@wireshark.org>

packaging/macosx/osx-app.sh

@@ -729,7 +729,9 @@ if [ -n "$CODE_SIGN_IDENTITY" ] ; then
 		exit 1
 	fi
 	for binary in $cs_binary_list ; do
-		codesign_file "$binary"
+		if [ -e "$binary" ];then
+			codesign_file "$binary"
+		fi
 	done
 
 	echo "Signing frameworks"