3rd party complete -C completions broken

[scop]

Describe the bug

SSIA. Broken by 95eef92, but I guess this is something to fix in __load_completion.

To reproduce

See debug trace.

Expected behavior

Versions (please complete the following information)

• Operating system name/distribution and version:
• bash version, echo "$BASH_VERSION":
• bash-completion version, (IFS=.; echo "${BASH_COMPLETION_VERSINFO[*]}"):

Additional context

Debug trace

$ vault + local cmd=vault
+ __load_completion vault
[...]
+ compfile=/home/scop/Documents/code/bash-completion/completions/_vault
+ [[ -d /home/scop/Documents/code/bash-completion/completions/_vault ]]
+ [[ -e /home/scop/Documents/code/bash-completion/completions/_vault ]]
+ . /home/scop/Documents/code/bash-completion/completions/_vault /usr/bin/vault
++ type /usr/bin/vault
++ complete -C '"/usr/bin/vault" 2>/dev/null' /usr/bin/vault
++ complete -p /usr/bin/vault
+ compspec='complete -C '\''"/usr/bin/vault" 2>/dev/null'\'' /usr/bin/vault'
+ extspecs=()
+ local -a extspecs
+ [[ -n '' ]]
+ [[ vault != */* ]]
+ complete -p vault
+ extspecs+=("$origcmd")
+ (( 1 != 0 ))
+ complete -C ''\''"/usr/bin/vault"' '2>/dev/null'\''' /usr/bin/vault vault
+ return 0
+ return 124
bash: command substitution: line 1: unexpected EOF while looking for matching `''
bash: command substitution: line 2: syntax error: unexpected end of file

$ complete -p vault
+ complete -p vault
complete -C ''\''"/usr/bin/vault"' vault