Fix liquibase bat (#4985)

* Fix environment variable handling in liquibase.bat
1: Don't error if JAVA_HOME is defined and surrounded by double-quotes
2: If auto-setting JAVA_HOME, fix double-backslash before jre
3: If auto-setting JAVA_HOME, remove quotes around JAVA_HOME

* Fix missing space before nested IF statement

liquibase-dist/src/main/archive/liquibase.bat

@@ -10,11 +10,14 @@ rem remove quotes around LIQUIBASE_HOME
 set LIQUIBASE_HOME=%LIQUIBASE_HOME:"=%
 
 rem remove quotes around JAVA_HOME if set
-if NOT "%JAVA_HOME%" == "" set JAVA_HOME=%JAVA_HOME:"=%
+if DEFINED JAVA_HOME if NOT JAVA_HOME == "" set JAVA_HOME=%JAVA_HOME:"=%
 
 rem set JAVA_HOME to local jre dir if not set
 if exist "%LIQUIBASE_HOME%\jre" if "%JAVA_HOME%"=="" (
-    set JAVA_HOME=%LIQUIBASE_HOME%\jre
+    set JAVA_HOME="%LIQUIBASE_HOME%jre"
+
+    rem remove quotes around JAVA_HOME
+    set JAVA_HOME=!JAVA_HOME:"=!
 )
 
 if NOT "%JAVA_HOME%" == "" if not exist "%JAVA_HOME%" (