[pre-commit] Fix execute and shebang lines

This commit removes the execute bit from several files
and remove the shebang lines from the devstack plugin.

While the devstack plugin is written in bash, it is not an executable
script. The devstack plugin is sourced by devstack as needed,
as such it is not executed in a subshell and the #!/bin/bash
lines are not used even when present.

Change-Id: I82ca22b7a47bf267fe6cf11f3e3519510108c146

.pre-commit-config.yaml

@@ -16,10 +16,8 @@ repos:
         files: .*\.json$
       - id: check-yaml
         files: .*\.(yaml|yml)$
-      # FIXME(sean-k-mooney): we currently have some files
-      # with incorrect permission, resolve this in a follow up
-      # - id: check-executables-have-shebangs
-      # - id: check-shebang-scripts-are-executable
+      - id: check-executables-have-shebangs
+      - id: check-shebang-scripts-are-executable
       # git
       - id: check-added-large-files
       - id: check-case-conflict