--delete-output-path no longer working with ng serve

Versions

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Angular CLI: 6.0.0-rc.5
Node: 8.11.1
OS: win32 x64
Angular: 6.0.0-rc.5
... cli, common, compiler, compiler-cli, core, forms, http
... language-service, platform-browser, platform-browser-dynamic
... router

Package                           Version
-----------------------------------------------------------
@angular-devkit/architect         0.5.7
@angular-devkit/build-angular     0.5.7
@angular-devkit/build-optimizer   0.5.7
@angular-devkit/core              0.5.7
@angular-devkit/schematics        0.5.7
@ngtools/json-schema              1.1.0
@ngtools/webpack                  6.0.0-rc.5
@schematics/angular               0.5.7
@schematics/update                0.5.7
rxjs                              6.0.0-uncanny-rc.7
typescript                        2.7.2
webpack                           4.5.0

Repro steps

• Create a new Angular App
• Try to run it using ng serve --host=0.0.0.0 --port=8100 --delete-output-path=false

Observed behavior

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Error is returned saying ```Unknown option: '--deleteOutputPath'```. There is no stack trace available

Desired behavior

Based on the source, I would expect that flag or its alias ‘dop’ to still work.

Mention any other details that might be useful (optional)

[timfogarty-row8]

What if the output path is under git control? Now the entire folder gets wiped out, including the .git folder.

[Selupsis]

Our build also requires work to be done in the output folder before the actual build, so the removal of this option is a big impact… Any feasible workarounds?