public: fix symlink of bootstrap

diff --git a/src/newslash_web/public/bootstrap b/src/newslash_web/public/bootstrap
index fe0f86b..f1c9d8d 120000 (symlink)
--- a/src/newslash_web/public/bootstrap
+++ b/src/newslash_web/public/bootstrap
@@ -1 +1 @@
-/usr/share/javascript/bootstrap
\ No newline at end of file
+../external/bootstrap-3.3.7/dist
\ No newline at end of file