remove win JAVA_HOME lookup because it has problems with spaces in th…

…e PATH

It'd be nice to replace this with something that works better. I asked someone to try

    for /f "delims=;" %%P IN (%PATH%) do if exist %%P\java.exe set JAVA_HOME=%%P..\

but it didn't work. Now, it'll print an error message about setting JAVA_HOME, which will work. For reference, the conversation was http://donttreadonme.co.uk/mirah/2012/07/16.html#message_16

distbin/_mirahvars.bat

@@ -15,9 +15,6 @@ rem ----- Verify and Set Required Environment Variables -----------------------
 
 if not "%JAVA_HOME%" == "" goto gotJava
 
-for %%P in (%PATH%) do if exist %%P\java.exe set JAVA_HOME=%%P..\
-if not "%JAVA_HOME%" == "" goto gotJava
-
 echo You must set JAVA_HOME to point at your JRE/JDK installation
 set MIRAH_BAT_ERROR=1
 exit /b 1