fix(help): remove dupe alias of check-mem in install

- when running ghost install --help the mem-check alias was appearing twice
- this is because the doctor options are loaded twice, once in start under setup, and once directly in install
- removing this extra load fixes the issue because aliases are additive

lib/commands/install.js

@@ -9,7 +9,6 @@ class InstallCommand extends Command {
     static configureOptions(commandName, yargs, extensions) {
         yargs = super.configureOptions(commandName, yargs, extensions);
         yargs = SetupCommand.configureOptions('setup', yargs, extensions, true);
-        yargs = DoctorCommand.configureOptions('doctor', yargs, extensions, true);
 
         return yargs;
     }

test/unit/commands/install-spec.js

@@ -12,15 +12,13 @@ describe('Unit: Commands > Install', function () {
     it('configureOptions adds setup & doctor options', function () {
         const superStub = sinon.stub().returnsArg(1);
         const setupStub = sinon.stub().returnsArg(1);
-        const doctorStub = sinon.stub().returnsArg(1);
 
         // Needed for extension
         class Command {}
         Command.configureOptions = superStub;
 
         const InstallCommand = proxyquire(modulePath, {
             './setup': {configureOptions: setupStub},
-            './doctor': {configureOptions: doctorStub},
             '../command': Command
         });
 
@@ -30,8 +28,6 @@ describe('Unit: Commands > Install', function () {
         expect(superStub.calledWithExactly('install', {yargs: true}, [{extensiona: true}])).to.be.true;
         expect(setupStub.calledOnce).to.be.true;
         expect(setupStub.calledWithExactly('setup', {yargs: true}, [{extensiona: true}], true)).to.be.true;
-        expect(doctorStub.calledOnce).to.be.true;
-        expect(doctorStub.calledWithExactly('doctor', {yargs: true}, [{extensiona: true}], true)).to.be.true;
     });
 
     describe('run', function () {