error MSB4126: configuration "release _shared|x86" invalid

### Steps to reproduce

Directory contents:
```
```

Command line
```
msbuild /clp:NoSummary /nologo /v:minimal /p:UseEnv=false /m /t:build /p:Configuration=release_shared samples_vs150.sln
```
### Expected behavior
A valid msbuild of the solution

### Actual behavior
C:\Users\fandre\Documents\git\poco-1.9.1\Foundation\samples\samples_vs150.sln.metaproj : error MSB4126: La configuration de solution spécifiée "release
_shared|x86" n'est pas valide. Spécifiez une configuration de solution valide à l'aide des propriétés Configuration et Platform (exemple : MSBuild.exe
Solution.sln /p:Configuration=Debug /p:Platform="Any CPU") ou laissez ces propriétés vides si vous voulez utiliser la configuration de solution par déf
aut. [C:\Users\fandre\Documents\git\poco-1.9.1\Foundation\samples\samples_vs150.sln]

[samples_vs150.sln.txt](https://github.com/Microsoft/msbuild/files/2069278/samples_vs150.sln.txt)

### Environment data
`msbuild /version` output: 15.7.179.6572

OS info:

If applicable, version of the tool that invokes MSBuild (Visual Studio, dotnet CLI, etc):
**********************************************************************
** Visual Studio 2017 Developer Command Prompt v15.7.3
** Copyright (c) 2017 Microsoft Corporation
**********************************************************************
[vcvarsall.bat] Environment initialized for: 'x86'