Restore even if cannot set writable permissions. Fixes #437

[bwmarkle]

@cssjoe says:

the message changed to: Total Upkeep - Restoration failed Could not copy file.: wp-config.php I chown 0:0 wp-config.php for the test restore. It still says it failed. Should it say success with errors, or partially restored?

I'm going to put this PR on hold so we can get some releases out today.

1. Looks like I missed some logic that needs to be accounted for.
2. Thus far, only 1 report. Edge case?

[codecov-io]

Codecov Report

Merging #447 (32c9ba5) into master (6d78a90) will increase coverage by 0.00%. The diff coverage is n/a.

@@            Coverage Diff            @@
##             master     #447   +/-   ##
=========================================
  Coverage     25.46%   25.46%           
  Complexity     2920     2920           
=========================================
  Files           202      202           
  Lines         14698    14697    -1     
=========================================
  Hits           3743     3743           
+ Misses        10955    10954    -1     

Impacted Files	Coverage Δ	Complexity Δ
admin/class-boldgrid-backup-admin-core.php	48.76% <ø> (+0.04%)	243.00 <0.00> (ø)

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[cssjoe]

This may need better result messages.

• Completes successfully
• Completed with errors; partially restored -- Maybe have an expandable file list
• Could not restore -- with the reason(s)