generate_workspace does not create automatically output directory if they do not exist

[damienmg]

$ bazel run //generate_workspace -- -a com.lesfurets:jenkins-pipeline-unit:1.0 -o /tmp/test
INFO: Analysed target //generate_workspace:generate_workspace.
INFO: Found 1 target...
Target //generate_workspace:generate_workspace up-to-date:
  bazel-bin/generate_workspace/generate_workspace.jar
  bazel-bin/generate_workspace/generate_workspace
INFO: Elapsed time: 0.277s, Critical Path: 0.02s
INFO: Build completed successfully, 1 total action

INFO: Running command line: bazel-bin/generate_workspace/generate_workspace -a com.lesfurets:jenkins-pipeline-unit:1.0 -o /tmp/test
Jun 28, 2017 6:34:20 PM com.google.devtools.build.workspace.maven.Resolver traverseDeps
INFO:   Downloading pom for com.lesfurets:jenkins-pipeline-unit:1.0
Jun 28, 2017 6:34:21 PM com.google.devtools.build.workspace.maven.Resolver traverseDeps
INFO:   Downloading pom for org.codehaus.groovy:groovy-all:2.4.6
Jun 28, 2017 6:34:23 PM com.google.devtools.build.workspace.maven.Resolver traverseDeps
INFO:   Downloading pom for com.cloudbees:groovy-cps:1.12
Jun 28, 2017 6:34:25 PM com.google.devtools.build.workspace.maven.Resolver traverseDeps
INFO:   Downloading pom for com.google.guava:guava:11.0.1
Jun 28, 2017 6:34:26 PM com.google.devtools.build.workspace.maven.Resolver traverseDeps
INFO:   Downloading pom for com.google.code.findbugs:jsr305:1.3.9
Jun 28, 2017 6:34:29 PM com.google.devtools.build.workspace.maven.Resolver traverseDeps
INFO:   Downloading pom for commons-io:commons-io:2.5
Jun 28, 2017 6:34:33 PM com.google.devtools.build.workspace.maven.Resolver traverseDeps
INFO:   Downloading pom for org.apache.ivy:ivy:2.4.0
Jun 28, 2017 6:34:33 PM com.google.devtools.build.workspace.output.BzlWriter write
SEVERE: Could not write /tmp/test/generate_workspace.bzl: /tmp/test/generate_workspace.bzl (No such file or directory)

[petroseskinder]

42 resolved this @kchodorow

[petroseskinder]

@kchodorow can we close this. #42 solved this.