buildman: Correct toolchain download feature

Commit d9088983 updated the ScanPath() function but not its documentation
and not all its callers.

This breaks the toolchain check after it is downloaded. Fix it.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Heiko Schocher <hs@denx.de>

tools/buildman/toolchain.py

@@ -465,11 +465,15 @@ class Toolchains:
         # Check that the toolchain works
         print 'Testing'
         dirpath = os.path.join(dest, path)
-        compiler_fname = self.ScanPath(dirpath, True)
-        if not compiler_fname:
+        compiler_fname_list = self.ScanPath(dirpath, True)
+        if not compiler_fname_list:
             print 'Could not locate C compiler - fetch failed.'
             return 1
-        toolchain = Toolchain(compiler_fname, True, True)
+        if len(compiler_fname_list) != 1:
+            print ('Internal error, ambiguous toolchains: %s' %
+                   (', '.join(compiler_fname)))
+            return 1
+        toolchain = Toolchain(compiler_fname_list[0], True, True)
 
         # Make sure that it will be found by buildman
         if not self.TestSettingsHasPath(dirpath):