Errors in Database.load should include input filename in the error message

[olafurpg]

I'm currently debugging an issue in how sbthost emits .semanticdb files during incremental compilation. The stack traces look like this

[info]   com.google.protobuf.InvalidProtocolBufferException: While parsing a protocol message, the input ended unexpectedly in the middle of a field.  This could mean either that the input has been truncated or that an embedded message misreported its own length.
[info]   at com.google.protobuf.InvalidProtocolBufferException.truncatedMessage(InvalidProtocolBufferException.java:82)
[info]   at com.google.protobuf.CodedInputStream$ArrayDecoder.skipRawBytes(CodedInputStream.java:1200)
[info]   at com.google.protobuf.CodedInputStream$ArrayDecoder.skipField(CodedInputStream.java:575)
[info]   at lang.meta.internal.semanticdb.schema.Database.mergeFrom(Database.scala:45)

it would be nice if the message included the filename that was being loaded. That would help me inspect its contents and see why it's wrong.