Use rm -f to avoid hang waiting on input in check_gemfile

In certain docker setups, the Gemfile.lock file winds up being
owned by the "wrong" user, so when the check_gemfile function
tries to remove and re-touch it, the rm command hangs up waiting
for a confirmation on "rm: remove write-protected regular file
'Gemfile.lock'?" The fix is to use rm -f which will not ask for
the confirmation.

Test plan:
* docker_dev_update and update_canvas both still work

Change-Id: Ie6f1be8d6b52284da59e2c0e4c55e1662fe2e7d2
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/253405
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
QA-Review: Charley Kline <ckline@instructure.com>
Product-Review: Charley Kline <ckline@instructure.com>
Reviewed-by: Ed Schiebel <eschiebel@instructure.com>

build/common_docker_build_steps.sh

@@ -72,7 +72,7 @@ function check_gemfile {
 'For historical reasons, the Canvas Gemfile.lock is not tracked by git. We may
 need to remove it before we can install gems, to prevent conflicting depencency
 errors.'
-    confirm_command 'rm Gemfile.lock' || true
+    confirm_command 'rm -f Gemfile.lock' || true
   fi
 
   # Fixes 'error while trying to write to `/usr/src/app/Gemfile.lock`'

script/common.sh

@@ -95,7 +95,7 @@ function rebase_canvas {
 
 function bundle_install {
   echo_console_and_log "  Installing gems (bundle install) ..."
-  rm Gemfile.lock* >/dev/null 2>&1
+  rm -f Gemfile.lock* >/dev/null 2>&1
   bundle install >>"$LOG" 2>&1
 }