ProjectExplorer: Use Utils::FileName in ProcessParameters

For the command and the working directory.

Change-Id: Ia69dc7100aeb57bb6e1b35f4dd4f3cf3763d8cda
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/libs/utils/environment.cpp

@@ -690,6 +690,11 @@ QString Environment::expandVariables(const QString &input) const
     return result;
 }
 
+FileName Environment::expandVariables(const FileName &variables) const
+{
+    return FileName::fromString(expandVariables(variables.toString()));
+}
+
 QStringList Environment::expandVariables(const QStringList &variables) const
 {
     return Utils::transform(variables, [this](const QString &i) { return expandVariables(i); });