Bug 1369665 - "mach vendor rust" has to export the OpenSSL lib folder. r=rillian

It's not enough to only export the include folder for openssl, but for
linking the lib folder is also necessary. Also DEP_OPENSSL_INCLUDE
shouldn't be set directly, because it's set by Cargo itself based
on the output of openssl-sys's build script.

MozReview-Commit-ID: Ijbx7STgCXq

--HG--
extra : rebase_source : 9f93d20f974eb85e0e96fdfb017a402a263330ef

python/mozbuild/mozbuild/vendor_rust.py

@@ -89,7 +89,7 @@ Please commit or stash these changes before vendoring, or re-run with `--ignore-
                      'Using OpenSSL in /usr/local/opt/openssl')
             return {
                 'OPENSSL_INCLUDE_DIR': '/usr/local/opt/openssl/include',
-                 'DEP_OPENSSL_INCLUDE': '/usr/local/opt/openssl/include',
+                'OPENSSL_LIB_DIR': '/usr/local/opt/openssl/lib',
             }
 
         self.log(logging.ERROR, 'openssl', {}, "OpenSSL not found!")