RUBY-2060 Pin mlaunch version on evergreen (#1621)

* pin mlaunch version

* remove keyword argument from spec

* Re-running tests

Author: Emily Giurleo

.evergreen/functions.sh

@@ -201,7 +201,7 @@ prepare_server_from_url() {
 
 install_mlaunch() {
   pythonpath="$MONGO_ORCHESTRATION_HOME"/python
-  pip install -t "$pythonpath" 'mtools[mlaunch]'
+  pip install -t "$pythonpath" -v 'mtools[mlaunch]==1.5.3'
   export PATH="$pythonpath/bin":$PATH
   export PYTHONPATH="$pythonpath"
 }

spec/integration/client_options_spec.rb

@@ -38,7 +38,7 @@
     end
   end
 
-  shared_examples_for 'auth mechanism that uses database or default auth source' do |default_auth_source:|
+  shared_examples_for 'auth mechanism that uses database or default auth source' do |default_auth_source|
     context 'where no database is provided' do
       context 'with URI options' do
         let(:credentials) { "#{user}:#{pwd}@" }
@@ -198,7 +198,7 @@
     let(:auth_mech_sym) { :mongodb_cr }
 
     it_behaves_like 'a supported auth mechanism'
-    it_behaves_like 'auth mechanism that uses database or default auth source', default_auth_source: 'admin'
+    it_behaves_like 'auth mechanism that uses database or default auth source', 'admin'
     it_behaves_like 'an auth mechanism that doesn\'t support auth_mech_properties'
   end
 
@@ -207,7 +207,7 @@
     let(:auth_mech_sym) { :scram }
 
     it_behaves_like 'a supported auth mechanism'
-    it_behaves_like 'auth mechanism that uses database or default auth source', default_auth_source: 'admin'
+    it_behaves_like 'auth mechanism that uses database or default auth source', 'admin'
     it_behaves_like 'an auth mechanism that doesn\'t support auth_mech_properties'
   end
 
@@ -216,7 +216,7 @@
     let(:auth_mech_sym) { :scram256 }
 
     it_behaves_like 'a supported auth mechanism'
-    it_behaves_like 'auth mechanism that uses database or default auth source', default_auth_source: 'admin'
+    it_behaves_like 'auth mechanism that uses database or default auth source', 'admin'
     it_behaves_like 'an auth mechanism that doesn\'t support auth_mech_properties'
   end
 
@@ -263,7 +263,7 @@
     let(:auth_mech_sym) { :plain }
 
     it_behaves_like 'a supported auth mechanism'
-    it_behaves_like 'auth mechanism that uses database or default auth source', default_auth_source: '$external'
+    it_behaves_like 'auth mechanism that uses database or default auth source', '$external'
     it_behaves_like 'an auth mechanism with ssl'
     it_behaves_like 'an auth mechanism that doesn\'t support auth_mech_properties'
   end