watchDirectories does not work with symbolic link

#### Investigative information

Please provide the following:

- Timestamp: 2018-09-15
- Function App version (1.0 or 2.0-beta): 2.0.1-beta.37
- Function App name: Local
- Function Language: Python

#### Repro steps

1. Create symbolic link to folder `ln -s ../src src`
2. Create host.json containing: `"watchDirectories": ["src"]`
2. Make any change to files inside src folder

#### Expected behavior

Expected the function web host to restart, but it does not pick any change.

#### Actual behavior

Because folder is a symbolic link, it does not watch files correctly.

#### Known workarounds

Also, tried adding `"watchDirectories": ["../src"]` but nothing works.

Start with the host.json watchDirectories setting and reproduce the reported case using a symbolic link from src to ../src. Trace how the host watches that directory, then verify that changing a file through the symlink causes the function web host to restart.

Written by the indexing model from the issue text.