JMeter.bat fails if JMETER_BIN is set and bin folder contains spaces

**mm kashiwabara** ([Bug 58415](https://bz.apache.org/bugzilla//show_bug.cgi?id=58415&redirect=false)):
Need quotes around a couple more paths in jmeter.bat (similar to https://github.com/apache/jmeter/issues/1731),

if .%JM_LAUNCH% == . set JM_LAUNCH=java.exe

should be

if ".%JM_LAUNCH%" == "." set JM_LAUNCH=java.exe

and
if .%JMETER_BIN% == . set JMETER_BIN=%~dp0

should be

if ".%JMETER_BIN%" == "." set JMETER_BIN=%~dp0

Wouldn't so much of a problem except that Windows put a space in the middle of the name for the default program folder....

Severity: normal
OS: All