Do not return error when package is already installed

Author: felipecrs

.gitignore

@@ -18,3 +18,4 @@ mongo.json
 out/
 sdkman-cli.iml
 target/
+bin/test/

src/main/bash/sdkman-install.sh

@@ -28,8 +28,8 @@ function __sdk_install() {
 
 	if [[ -d "${SDKMAN_CANDIDATES_DIR}/${candidate}/${VERSION}" || -L "${SDKMAN_CANDIDATES_DIR}/${candidate}/${VERSION}" ]]; then
 		echo ""
-		__sdkman_echo_red "Stop! ${candidate} ${VERSION} is already installed."
-		return 1
+		__sdkman_echo_yellow "${candidate} ${VERSION} is already installed."
+		return 0
 	fi
 
 	if [[ ${VERSION_VALID} == 'valid' ]]; then

src/test/cucumber/install_candidate.feature

@@ -35,8 +35,8 @@ Feature: Install Candidate
 		And the candidate "grails" version "1.3.9" is available for download
 		And the candidate "grails" version "1.3.9" is already installed and default
 		When I enter "sdk install grails 1.3.9"
-		Then I see "Stop! grails 1.3.9 is already installed."
-		And the exit code is 1
+		Then I see "grails 1.3.9 is already installed."
+		And the exit code is 0
 
 	Scenario: Install a candidate and auto-answer to make it default
 		Given the system is bootstrapped

src/test/cucumber/local_developement_versions.feature

@@ -17,7 +17,8 @@ Feature: Local Development Versions
 		And the candidate "groovy" version "2.1-SNAPSHOT" is already linked to "/tmp/groovy-core"
 		And the system is bootstrapped
 		When I enter "sdk install groovy 2.1-SNAPSHOT /tmp/groovy-core"
-		Then I see "Stop! groovy 2.1-SNAPSHOT is already installed."
+		Then I see "groovy 2.1-SNAPSHOT is already installed."
+		And the exit code is 0
 		And the candidate "groovy" version "2.1-SNAPSHOT" is linked to "/tmp/groovy-core"
 
 	Scenario: Uninstall a local development version

src/test/cucumber/service_unavailable.feature

@@ -68,7 +68,8 @@ Feature: Service Unavailable
 		Given the candidate "grails" version "2.1.0" is already installed and default
 		And the system is bootstrapped
 		When I enter "sdk install grails 2.1.0"
-		Then I see "Stop! grails 2.1.0 is already installed."
+		Then I see "grails 2.1.0 is already installed."
+		And the exit code is 0
 
 	# uninstall command