Fix silly pathspec bug in git-ls-files

The "verify_pathspec()" function doesn't test for ending NUL character in 
the pathspec, causing some really funky and unexpected behaviour. It just 
happened to work in the cases I had tested.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/ls-files.c b/ls-files.c
--- a/ls-files.c
+++ b/ls-files.c

@@ -496,7 +496,7 @@ static void verify_pathspec(void)
 			char c = n[i];
 			if (prev && prev[i] != c)
 				break;
-			if (c == '*' || c == '?')
+			if (!c || c == '*' || c == '?')
 				break;
 			if (c == '/')
 				len = i+1;