Remove references to guide-conditions

std::condition was removed in 454882d
but there are still links to the guide. Removing them.

Author: gmjosack

configure

@@ -803,7 +803,6 @@ do
     make_dir $h/test/doc-guide-pointers
     make_dir $h/test/doc-guide-container
     make_dir $h/test/doc-guide-tasks
-    make_dir $h/test/doc-guide-conditions
     make_dir $h/test/doc-complement-cheatsheet
     make_dir $h/test/doc-rust
 done

src/doc/index.md

@@ -19,7 +19,6 @@ li {list-style-type: none; }
 * [Foreign Function Interface](guide-ffi.html)
 * [Macros](guide-macros.html)
 * [Testing](guide-testing.html)
-* [Conditions](guide-conditions.html)
 * [Rust's Runtime](guide-runtime.html)
 
 # Libraries