[SPARK-10359][PROJECT-INFRA] Multiple fixes to dev/test-dependencies.sh script

This patch includes multiple fixes for the `dev/test-dependencies.sh` script (which was introduced in #10461):

- Use `build/mvn --force` instead of `mvn` in one additional place.
- Explicitly set a zero exit code on success.
- Set `LC_ALL=C` to make `sort` results agree across machines (see https://stackoverflow.com/questions/28881/).
- Set `should_run_build_tests=True` for `build` module (this somehow got lost).

Author: Josh Rosen <joshrosen@databricks.com>

Closes #10543 from JoshRosen/dep-script-fixes.

dev/sparktestsupport/modules.py

@@ -402,7 +402,8 @@ build = Module(
     source_file_regexes=[
         ".*pom.xml",
         "dev/test-dependencies.sh",
-    ]
+    ],
+    should_run_build_tests=True
 )
 
 ec2 = Module(

dev/test-dependencies.sh

@@ -22,6 +22,10 @@ set -e
 FWDIR="$(cd "`dirname $0`"/..; pwd)"
 cd "$FWDIR"
 
+# Explicitly set locale in order to make `sort` output consistent across machines.
+# See https://stackoverflow.com/questions/28881 for more details.
+export LC_ALL=C
+
 # TODO: This would be much nicer to do in SBT, once SBT supports Maven-style resolution.
 
 # NOTE: These should match those in the release publishing script
@@ -37,7 +41,7 @@ HADOOP_PROFILES=(
 # resolve Spark's internal submodule dependencies.
 
 # See http://stackoverflow.com/a/3545363 for an explanation of this one-liner:
-OLD_VERSION=$(mvn help:evaluate -Dexpression=project.version|grep -Ev '(^\[|Download\w+:)')
+OLD_VERSION=$($MVN help:evaluate -Dexpression=project.version|grep -Ev '(^\[|Download\w+:)')
 TEMP_VERSION="spark-$(date +%s | tail -c6)"
 
 function reset_version {
@@ -100,3 +104,5 @@ for HADOOP_PROFILE in "${HADOOP_PROFILES[@]}"; do
     exit 1
   fi
 done
+
+exit 0