The whole git changed list opens if git compare called from file context menu

[iedexmain1]

Steps to reproduce:

1. Make changes in several files.
2. Select one of the changed files in project explorer.
3. Call its context menu by clicking right mouse button on it.
4. Click Git -> Compare with latest version.
   Wrong: list of all git changed files will be opened.
   Expected: git compare window of selected file should be opened.

• Expected behavior: after clicking on the fires item the Compare button should be enabked
• Observed behavior: after clicking on the fires item the Compare button still disabled
• Che version: 4.5.0
• OS and version: Ubuntu OS 14.0
• Docker version: 1.11.2
• Che install: local bundle

Additional information: GitCompareTest