[c-index-test] Do install c-index-test because it's not just for tests,
it's also setup as 'INTERNAL_TOOL'.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@167432 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/c-index-test/Makefile b/tools/c-index-test/Makefile
index 09eff0f..b81678b 100644
--- a/tools/c-index-test/Makefile
+++ b/tools/c-index-test/Makefile
@@ -17,9 +17,6 @@
 # No plugins, optimize startup time.
 TOOL_NO_EXPORTS = 1
 
-# Don't install this. It is used for tests.
-NO_INSTALL = 1
-
 # Include this here so we can get the configuration of the targets that have
 # been configured for construction. We have to do this early so we can set up
 # LINK_COMPONENTS before including Makefile.rules