Tweak proc_macro test to correctly test case.

Minor change causes the test to actually test the case instead of always
passing regardless of the fix that adds the host dependency directory to
the library search path.

Author: lucaskolstad

tests/test.rs

@@ -2816,10 +2816,10 @@ fn find_dependency_of_proc_macro_dependency_with_target() {
             proc-macro = true
 
             [dependencies]
-            dep_of_proc_macro_dep = "^0.1"
+            bar = "^0.1"
         "#)
         .file("proc_macro_dep/src/lib.rs", r#"
-            extern crate dep_of_proc_macro_dep;
+            extern crate bar;
             extern crate proc_macro;
             use proc_macro::TokenStream;
 
@@ -2828,7 +2828,11 @@ fn find_dependency_of_proc_macro_dependency_with_target() {
                 "".parse().unwrap()
             }
         "#);
-    Package::new("dep_of_proc_macro_dep", "0.1.0").publish();
+    Package::new("foo", "0.1.0").publish();
+    Package::new("bar", "0.1.0")
+        .dep("foo", "0.1")
+        .file("src/lib.rs", "extern crate foo;")
+        .publish();
     workspace.build();
     assert_that(workspace.cargo("test").arg("--all").arg("--target").arg(rustc_host()),
                 execs().with_status(0));