Add support to the FlumeNode windows installer to detect 32-bit Java Installations (read JAVA_HOME properly) when running on 64 bit windows machines.

Currently the nsis installer script template contains support for detecting the Java Installation (JAVA_HOME) correctly only if the architecture of the JDK installed is same as the base architecture of the base machine. Possibly, flume also works fine with 32-bit JDK on 64-bit machines. But in this case, the nsis script does not automatically detect the Java installation directory since on 64 bit machines, all 32-bit software related registry keys are emulated under the virtual registry, HKLM\SOFTWARE\Wow6432Node\ (instead of being directly under HKLM\SOFTWARE). The patch fixes this by adding this check to the nsi template which is used for generating the nsis script with "ant winstall-filter"