Make command is overridden in Deploy even if it's empty

If "Make" step is defined in Deployment settings, the default make command is overridden even if the corresponding field is left empty, so that deployment can't be executed

Compile output:

16:14:57: Running steps for project untitled...
16:14:57: Configuration unchanged, skipping qmake step.
16:14:57: Starting: "C:\Qt\Qt5.7.0_mingw\Tools\mingw530_32\bin\mingw32-make.exe"
C:/Qt/Qt5.7.0_mingw/Tools/mingw530_32/bin/mingw32-make -f Makefile.Debug
mingw32-make[1]: Entering directory 'D:/devel/temp/build-untitled-Qt_5_7_0_mingw530_32-Debug'
mingw32-make[1]: Nothing to be done for 'first'.
mingw32-make[1]: Leaving directory 'D:/devel/temp/build-untitled-Qt_5_7_0_mingw530_32-Debug'
16:14:57: The process "C:\Qt\Qt5.7.0_mingw\Tools\mingw530_32\bin\mingw32-make.exe" exited normally.
16:14:57: Could not start process "" install
Error while building/deploying project untitled (kit: Qt 5.7.0 (mingw530_32))
When executing step "Make"
16:14:57: Elapsed time: 00:00.

Steps to reproduce:
1. Create a new project
2. Go to Projects -> Run
3. Add deploy step -> Make
4. Enter "install" in Make arguments
5. Build & deploy

Workaround:
1. Enter actual path to "make" in the override field