[windows] Adjust resources for Windows Docker Machine

The new default values are:

- RACKER_WDM_VCPUS: 4
- RACKER_WDM_MEMORY: 4096 MB

Author: amotl

doc/winrunner.rst

@@ -65,13 +65,13 @@ Resources
 =========
 
 When creating the `Windows Docker Machine`_ virtual machine, the program will
-configure it to use 6 VCPUs and 6144 MB system memory by default.
+configure it to use 4 VCPUs and 4 GB system memory by default.
 
 In order to adjust those values, use these environment variables before
 invoking the later commands::
 
-    export RACKER_VM_VCPUS=12
-    export RACKER_VM_MEMORY=8192
+    export RACKER_WDM_VCPUS=8
+    export RACKER_WDM_MEMORY=8192
 
 If you want to adjust the values after the initial deployment, you will have to
 reset the `Windows Docker Machine`_ installation directory. For example, it is:

postroj/winrunner.py

@@ -24,8 +24,8 @@
 
 class WinRunner:
 
-    VCPUS = os.environ.get("RACKER_WDM_VCPUS", 6)
-    MEMORY = os.environ.get("RACKER_WDM_MEMORY", 6144)
+    VCPUS = os.environ.get("RACKER_WDM_VCPUS", 4)
+    MEMORY = os.environ.get("RACKER_WDM_MEMORY", 4096)
 
     def __init__(self, image: str):
         self.image_base = image