Updated things related to the vmware-iso builder to include @azr's suggestions.

builder/vmware/common/hw_config.go

@@ -34,12 +34,10 @@ func (c *HWConfig) Prepare(ctx *interpolate.Context) []error {
 	// Hardware and cpu options
 	if c.CpuCount < 0 {
 		errs = append(errs, fmt.Errorf("An invalid number of cpus was specified (cpus < 0): %d", c.CpuCount))
-		c.CpuCount = 0
 	}
 
 	if c.MemorySize < 0 {
 		errs = append(errs, fmt.Errorf("An invalid amount of memory was specified (memory < 0): %d", c.MemorySize))
-		c.MemorySize = 0
 	}
 
 	// Peripherals
@@ -59,7 +57,7 @@ func (c *HWConfig) Prepare(ctx *interpolate.Context) []error {
 		c.Serial = "none"
 	}
 
-	return nil
+	return errs
 }
 
 /* parallel port */

website/source/docs/builders/vmware-iso.html.md.erb

@@ -99,7 +99,6 @@ builder.
     specified, the default is `10s` or 10 seconds.
 
 -   `cpus` (number) - The number of cpus to use when building the VM.
-    Defaults to building with just one.
 
 -   `cdrom_adapter_type` (string) - The adapter type (or bus) that will be used
     by the cdrom device. This is chosen by default based on the disk adapter
@@ -225,7 +224,7 @@ builder.
     and `iso_url` is used. Only one of `iso_url` or `iso_urls` can be specified.
 
 -   `memory` (number) - The amount of memory to use when building the VM
-    in megabytes. Defaults to `512` megabytes.
+    in megabytes.
 
 -   `network` (string) - This is the network type that the virtual machine will
     be created with. This can be one of the generic values that map to a device