Limit number of candidates for executables

This change ensures that the first match of an executable in the path
is retured instead of a list of candidates. This prevents a CDI spec,
for example, from containing multiple entries for a single executable
(e.g. nvidia-smi).

Signed-off-by: Evan Lezar <elezar@nvidia.com>

internal/lookup/executable.go

@@ -41,6 +41,7 @@ func newExecutableLocator(logger *log.Logger, root string, paths ...string) *exe
 		WithRoot(root),
 		WithSearchPaths(paths...),
 		WithFilter(assertExecutable),
+		WithCount(1),
 	)
 
 	l := executable{