PTF IP22987 fixes APAR IC58466

This fix handles the following situation:
The Net Search Extender is not able to install
silently using the -s option of db2nse_install.
This fix now ensures that NSE is able to install
silently. Therefor the usage message has been 
changed too. 

Installation on LinuxAMD64:
===========================
1. Stop NSE and DB2
2. Uninstall NSE
3. As root: untar package C198WML.tar.gz in an empty directory 
4. Change to directory linuxAMD64 
5. For a common installation execute nsesetup.sh and follow the instructions
   OR
   run db2nse_install <tar.gz-archive> -s <DB2INSTALLPATH> to install silently  
 

Note: After you have installed Net Search Extender,  
run db2iupdt on all instances.