[PATCH] contrib/completion: escape the forward slash in __git_match_ctag

The current definition results in an incorrect expansion of the term under zsh.
For instance "/^${1////\\/}/" under zsh with the argument "hi" results in:
    /^/\/h/\/i/

This results in an output similar to this when trying to complete `git grep
chartab` under zsh:

    :: git grep chartabawk: cmd. line:1: /^/\/c/\/h/\/a/\/r/\/t/\/a/\/b/ { print $1 }
    awk: cmd. line:1:    ^ backslash not last character on line
    awk: cmd. line:1: /^/\/c/\/h/\/a/\/r/\/t/\/a/\/b/ { print $1 }
    awk: cmd. line:1:    ^ syntax error

Leaving the prompt in a goofy state until the user hits a key.

Escaping the literal / in the parameter expansion (using "/^${1//\//\\/}/")
results in:
    /^chartab/

allowing the completion to work correctly.

This formulation also works under bash.

Signed-off-by: John Szakmeister <redacted>
---

I've been bit by this bug quite a bit, but didn't have time to track it down
until today.  I hope the proposed solution is acceptable.

-John

 contrib/completion/git-completion.bash | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index c21190d..a899234 100644
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash

@@ -1305,7 +1305,7 @@ _git_gitk ()
 }
 
 __git_match_ctag() {
-	awk "/^${1////\\/}/ { print \$1 }" "$2"
+	awk "/^${1//\//\\/}/ { print \$1 }" "$2"
 }
 
 _git_grep ()

-- 
2.3.1