remove unsupported os versions from test.

Author: psabhay

.travis.yml

@@ -37,10 +37,6 @@ env:
     DISTRIBUTION=ubuntu
     DIST_VERSION=16_04-builded
     MONGODB_VERSION=3.4
-  - >
-    DISTRIBUTION=ubuntu-upstart
-    DIST_VERSION=14.04
-    MONGODB_VERSION=4.2
   - >
     DISTRIBUTION=ubuntu-upstart
     DIST_VERSION=14.04
@@ -65,10 +61,6 @@ env:
     DISTRIBUTION=debian
     DIST_VERSION=9-builded
     MONGODB_VERSION=3.6
-  - >
-    DISTRIBUTION=debian
-    DIST_VERSION=8-builded
-    MONGODB_VERSION=4.2
   - >
     DISTRIBUTION=debian
     DIST_VERSION=8-builded