Bug 73024 - replace getHash() with getFileSHA1Sum()

Instance of 'FilePage' has no 'getHash' member.
Use FilePage.getFileSHA1Sum().

Bug: 73024

Change-Id: Id4e13e57f46c9dd088bea0b80eea374fab959f2f
Merge "Bug 73024 - replace getHash() with getFileSHA1Sum()"