Avoid build errors if build couldnt be deleted or dist already existed

Author: Kuuuube

build.ps1

@@ -1,9 +1,14 @@
 cargo build --release
 if (Test-Path ./build) {
-    Remove-Item -Path ./build -Recurse
+    Remove-Item -Path ./build/* -Recurse
+} else {
+    New-Item -Path ./build -ItemType directory > $null
+}
+if (Test-Path ./dist) {
+    Remove-Item -Path ./dist/* -Recurse
+} else {
+    New-Item -Path ./dist -ItemType directory > $null
 }
-New-Item -Path ./build -ItemType directory > $null
-New-Item -Path ./dist -ItemType directory > $null
 Copy-Item -Path ./target/release/tabletdrivercleanup.exe -Destination ./build
 Copy-Item -Path ./eng/dump.bat -Destination ./build
 Copy-Item -Path ./eng/dry_run.bat -Destination ./build