Make the new installer work with existing installations (made with the old installer)

scripts/Start Stable Diffusion UI.cmd

@@ -1,3 +1,10 @@
+@echo off
+
+@REM Delete the post-activate hook from the old installer
+@if exist "installer\etc\conda\activate.d\post_activate.bat" (
+    del "installer\etc\conda\activate.d\post_activate.bat"
+)
+
 @call installer\Scripts\activate.bat
 
 @call conda-unpack
@@ -5,6 +12,8 @@
 @call conda --version
 @call git --version
 
+@cd installer
+
 @call scripts\on_env_start.bat
 
 @pause

scripts/on_env_start.bat

@@ -4,6 +4,8 @@
 
 set PATH=C:\Windows\System32;%PATH%
 
+@cd ..
+
 if exist "scripts\config.bat" (
     @call scripts\config.bat
 )