Don't Create Variable Policy for PlatformRecovery#### if SetVariable …

…Failed (#440)

## Description

A variable policy is automatically applied when
EfiBootManagerLoadOptionToVariable() is used to set the
PlatformRecovery#### variable. If the attempt to set the
PlatformRecovery#### fails, we should not register a variable policy.

- [x] Impacts functionality?
- **Functionality** - Does the change ultimately impact how firmware
functions?
- Examples: Add a new library, publish a new PPI, update an algorithm,
...
- [x] Impacts security?
- **Security** - Does the change have a direct security impact on an
application,
    flow, or firmware?
  - Examples: Crypto algorithm change, buffer overflow fix, parameter
    validation improvement, ...
- [ ] Breaking change?
- **Breaking change** - Will anyone consuming this change experience a
break
    in build or boot behavior?
- Examples: Add a new library class, move a module to a different repo,
call
    a function in a new library class in a pre-existing module, ...
- [ ] Includes tests?
  - **Tests** - Does the change include any explicit test code?
  - Examples: Unit tests, integration tests, robot tests, ...
- [ ] Includes documentation?
- **Documentation** - Does the change contain explicit documentation
additions
    outside direct code modifications (and comments)?
- Examples: Update readme file, add feature readme file, link to
documentation
    on an a separate Web page, ...

## How This Was Tested

Tested using the BootAuditTestApp on Q35

## Integration Instructions

N/A

MdeModulePkg/Include/Library/UefiBootManagerLib.h

@@ -155,7 +155,14 @@ EfiBootManagerVariableToLoadOption (
   );
 
 /**
-  Create the Boot#### or Driver#### variable from the load option.
+  // MU_CHANGE START
+  Create the Boot####, Driver####, SysPrep####, PlatformRecovery#### variable
+  from the load option.
+
+  If the OptionNumber is LoadOptionTypePlatformRecovery and the call to
+  SetVariable was successful, a lock now variable policy will be registered
+  for the PlatformRecovery#### variable.
+  // MU_CHANGE END
 
   @param  LoadOption      Pointer to the load option.
 

MdeModulePkg/Library/UefiBootManagerLib/BmLoadOption.c

@@ -166,6 +166,12 @@ BmGetFreeOptionNumber (
   Create the Boot####, Driver####, SysPrep####, PlatformRecovery#### variable
   from the load option.
 
+  // MU_CHANGE START
+  If the OptionNumber is LoadOptionTypePlatformRecovery and the call to
+  SetVariable was successful, a lock now variable policy will be registered
+  for the PlatformRecovery#### variable.
+  // MU_CHANGE END
+
   @param  LoadOption      Pointer to the load option.
 
   @retval EFI_SUCCESS     The variable was created.
@@ -262,6 +268,13 @@ structure.
                   );
   FreePool (Variable);
 
+  // MU_CHANGE START: Don't register a variable policy if the SetVariable call failed
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  // MU_CHANGE END
+
   // MU_CHANGE - Move RegisterBasicVariablePolicy after SetVariable for OptionName
   if (Option->OptionType == LoadOptionTypePlatformRecovery) {
     //