Align MANIFEST.MF plugin name with repo and Bazel name
Align MANIFEST.MF plugin name with repo and Bazel name

This plugin is named 'delete-project' in its Gerrit repo and Bazel
build file. Align the MANIFEST.MF name with the correct one, including
the hyphen '-'.

Change-Id: I4a6a00f78013cbb4d4168ea9a0ee8fd8cc1bece3

GerritCodeReview/plugins_delete-project,GerritCodeReview/plugins_delete-project,GerritCodeReview/plugins_delete-project,GerritCodeReview/plugins_delete-project