Changes

Prepare 4.5.2-SNAPSHOT builds

Change-Id: I8485de1f3f63dc9ec445b8fb08093ca144aedc59
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

Don't flag a packfile invalid if opening existing file failed

A packfile random file open operation may fail with a
FileNotFoundException even if the file exists, possibly
for the temporary lack of resources.

Instead of managing the FileNotFoundException as any generic
IOException it is best to rethrow the exception but prevent
the packfile for being flagged as invalid until it is actually
opened and read successfully or unsuccessfully.

Bug: 514170
Change-Id: Ie37edba2df77052bceafc0b314fd1d487544bf35
Signed-off-by: Luca Milanesio <luca.milanesio@gmail.com>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

Only mark packfile invalid if exception signals permanent problem

Add NoPackSignatureException and UnsupportedPackVersionException to
explicitly mark permanent unrecoverable problems with a pack

Assume problem with a pack is permanent only if we are sure the
exception signals a non-transient problem we can't recover from:
- AccessDeniedException: we lack permissions
- CorruptObjectException: we detected corruption
- EOFException: file ended unexpectedly
- NoPackSignatureException: pack has no pack signature
- NoSuchFileException: file has gone missing
- PackMismatchException: pack no longer matches its index
- UnpackException: unpacking failed
- UnsupportedPackIndexVersionException: unsupported pack index version
- UnsupportedPackVersionException: unsupported pack version

Do not attempt to handle Errors since they are thrown for serious
problems applications should not try to recover from.

Change-Id: I2c416ce2b0e23255c4fb03a3f9a0ee237f7a484a
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>