[PATCH] perf: Clean corpus and caches in distclean, not clean

[Austin Clements]

Previously, we cleaned the downloaded performance corpus and the
cached indexes on 'make clean'.  This seems heavy-handed, since these
take a long time to download, unpack, and index.  They also aren't
make targets to begin with.  Move cleaning these to 'make distclean'.
This isn't exactly the right meaning of "distclean", but it's closer.
---
 performance-test/Makefile.local | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/performance-test/Makefile.local b/performance-test/Makefile.local
index e47219a..d97e56d 100644
--- a/performance-test/Makefile.local
+++ b/performance-test/Makefile.local
@@ -39,4 +39,5 @@ $(TXZFILE):
 download-corpus:
 	wget -O ${TXZFILE} ${DEFAULT_URL}
 
-CLEAN := $(CLEAN) $(dir)/tmp.* $(dir)/log.* $(dir)/corpus $(dir)/notmuch.cache.*
+CLEAN := $(CLEAN) $(dir)/tmp.* $(dir)/log.*
+DISTCLEAN := $(dir)/corpus $(dir)/notmuch.cache.*
-- 
1.8.4.rc3