dsl-clc should pass relative DSL paths to dsl-compiler

[melezov]

Currently, it is sending platform-dependent file paths such as:

r:\a\dsl\a.dsl
/home/melezov/foo/model/foo.dsl

This puts the absolute paths in the SQL migration script, where it should be relative, and platform-independent:

dsl/a.dsl
model/foo.dsl

dsl-compiler works with / as path separator on Windows, so replacing \ with / should work

[zapov]

Fixed.