src: change to use /bin/sh instead of /bin/bash (#57)

Some container runtimes are intentionally constraned (e.g. alpine).
In these cases, the container may not have `/bin/bash` on the system.
This commit modifies the `runPrep` and `startProcess` functions to
use `/bin/sh` instead of `/bin/bash`.

See also: appsody/appsody#695

Co-authored-by: Kyle G. Christianson <[email protected]>
Co-authored-by: rykal-nate <[email protected]>

main.go

@@ -355,7 +355,7 @@ func killProcess(theProcessType ProcessType, checkAttempts int) error {
 */
 func runPrep(commandString string, interactive bool) (*exec.Cmd, error) {
 	var err error
-	cmd := exec.Command("/bin/bash", "-c", commandString)
+	cmd := exec.Command("/bin/sh", "-c", commandString)
 	ControllerDebug.log("Set workdir:  " + workDir)
 	cmd.Dir = workDir
 	if interactive {
@@ -376,7 +376,7 @@ func runPrep(commandString string, interactive bool) (*exec.Cmd, error) {
 */
 func startProcess(commandString string, theProcessType ProcessType, interactive bool) (*exec.Cmd, error) {
 	var err error
-	cmd := exec.Command("/bin/bash", "-c", commandString)
+	cmd := exec.Command("/bin/sh", "-c", commandString)
 	ControllerDebug.log("Set workdir:  " + workDir)
 	cmd.Dir = workDir
 	if interactive {