Add manually triggered builders to build conda environment CIPD package.

masters/master.chromium.infra/slaves.cfg

Index: masters/master.chromium.infra/slaves.cfg
diff --git a/masters/master.chromium.infra/slaves.cfg b/masters/master.chromium.infra/slaves.cfg
index 147182ff39a5bad889980bef0bb17375302c63f5..77502f44a5962be6b87f42821cef6b4d4a1b4fa9 100644
--- a/masters/master.chromium.infra/slaves.cfg
+++ b/masters/master.chromium.infra/slaves.cfg
@@ -9,6 +9,7 @@ slaves = [
   {
     'master': 'Infra',
     'builder': [
+      'conda-cipd-pkg-trusty-64',
       'infra-continuous-trusty-64',
       'luci-gae-trusty64',
       'luci-go-trusty64',
@@ -68,6 +69,7 @@ slaves = [
   {
     'master': 'Infra',
     'builder': [
+      'conda-cipd-pkg-mac-10.9-64',
       'infra-continuous-mac-10.9-64',
       'luci-go-osx',
     ],
@@ -111,6 +113,7 @@ slaves = [
   {
     'master': 'Infra',
     'builder': [
+      'conda-cipd-pkg-win-64',
       'infra-continuous-win-64',
       'luci-go-win64',
     ],